Reasoning:

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  •Judgement

Present: President ELIAS; Vice-President SETTE-CAMARA; Judges LACHS, MOROZOV, NAGENDRA SINGH, RUDA, MOSLER, ODA, AGO, ELKHANI, SCHWEBEL, Sir Robert JENNINGS, DE LACHARRIERE, MBAYE, BEDJAOUI; Judge ad hoc COLLIARD; Registrar TORRES BERNARDEZ.

In the case concerning military and paramilitary activities in and against Nicaragua, between the Republic of Nicaragua, represented by
H.E. Mr. Carlos Arguello Gomez, Ambassador, as Agent and Counsel,
Mr. Ian Brownlie, Q.C., F.B.A., Chichele Professor of Public International Law in the University of Oxford; Fellow of All Souls College, Oxford,
Hon. Abram Chayes, Felix Frankfurter Professor of Law, Harvard Law School; Fellow, American Academy of Arts and Sciences,
Mr. Alain Pellet, Professor at the University of Paris-Nord and the Institut d'Etudes Politiques de Paris,
Mr. Paul S. Reichler, Reichler and Appelbaum, Washington, D.C.; Member of the Bar of the United States Supreme Court; Member of the Bar of the District of Columbia, as Counsel and Advocates,
Mr. Augusto Zamora Rodriguez, Legal Adviser to the Foreign Ministry of the Republic of Nicaragua, Miss Judith C. Appelbaum, Reichler and Appelbaum, Washington, D C.; Member of the Bars of the District of Columbia and the State of California, Mr. Paul W. Khan, Reichler and Appelbaum, Washington, D.C., Member of the Bar of the District of Columbia as Counsel

and the United States of America, represented by  
Hon. Davis R. Robinson. Legal Adviser, United States Department of State, as Agent and Counsel, Mr. Daniel W. McGovern, Principal Deputy Legal Adviser, United States Department of State,  
Mr. Patrick M. Norton, Assistant Legal Adviser, United States Department of State, as Deputy-Agents and Counsel,  
Mr. Ted A. Borek, Assistant Legal Adviser, United States Department of State,  
Mr. Myres S. McDougal, Sterling Processor of Law Emeritus, Yale University, Yale Law School, New Haven, Connecticut; Distinguished Visiting Professor of Law, New York Law School, New York, New York.
Mr. John Norton Moore, Walter L. Brown Professor of Law, University of  Virginia School of Law, Charlottesville, Virginia,  Mr. Fred L. Morrison, Professor of Law, the Law School of the University of Minnesota, Minneapolis, Minnesota,  Mr. Stefan A. Riesenfeld, Professor of Law, University of California, School of Law, Berkeley, California, and Hastings College of the Law, San Francisco, California,  Mr. Louis B. Sohn, Woodruff Professor of International Law, University of Georgia School of Law, Athens, Georgia; Bemis Professor of International Law Emeritus, Harvard Law School, Cambridge, Massachusetts, as Counsel,  
Ms. Frances A. Armstrong. Attorney-Adviser.  Office of the Legal Adviser, United States Department of State,  
Mr. Michael J. Danaher, Member of the Bar of the State of California,  
Ms. Joan E. Donoghue, Attorney-Adviser, Office of the Legal Adviser, United States Department of State, 
Ms. Mary W. Ennis, Attorney-Adviser, Office of the Legal Adviser, United States Department of State,  
Mr. Peter M. Olson, Attorney-Adviser, Office of the Legal Adviser, United States Department of State,  
Mr. Jonathan B. Schwartz, Attorney-Adviser, Office of the Legal Adviser, United States Department of State,  
Ms. Jamison M. Selby, Attorney-Adviser, Office of the Legal Adviser, United States Department of State,  
Mr. George Taft, Attorney-Adviser, Office of the Legal Adviser, United States Department of State.  
Ms. Gayle R. Teicher, Attorney-Adviser, Office of the Legal Adviser, United States, Department of State, as Attorney-Advisers.

THE COURT, composed as above, delivers the following Judgment:

1.  On 9 April 1984 the Ambassador of the Republic of Nicaragua to the Netherlands filed in the Registry of the Court an Application instituting proceedings against the United States of America in respect of a dispute concerning responsibility for military and paramilitary activities in and against Nicaragua. In order to found the jurisdiction of the Court the Application relied on declarations made by the Parties accepting the compulsory jurisdiction of the Court under Article 36 of its Statute.

2.  Pursuant to Article 40, paragraph 2, of the Statute, the Application was at once communicated to the Government of the United States of America.  In accordance with paragraph 3 of that Article, all other States entitled to appear before the Court were notified of the Application.

3.  At the same time as the Application was filed, the Republic of Nicaragua also filed a request for the indication of provisional measures under Article 41 of the Statute.  By a letter from the United States Ambassador at The Hague to the Registrar dated 13 April 1984, and in the course of the oral proceedings held on the request by Nicaragua for the indication of provisional measures, the United States of America contended (inter alia) that the Court was without jurisdiction to deal with the Application, and requested that the proceedings be terminated by the removal of the case from the list.  By an Order dated 16 May 1984, the Court rejected the request of the United States for removal of the case from the list, indicated, pending its final decision in the proceedings, certain provisional measures, and decided that, until the Court delivers its final judgment in the case, it would keep the matters covered by the Order continuously under review.

4.  By the said Order of 10 May 1984, the Court further decided that the written proceedings in the case should first be addressed to the questions of the jurisdiction of the Court to entertain the dispute and of the admissibility of the Application.  By an Order dated 14 May 1984, the President of the Court fixed time-limits for the filing of a Memorial by the Republic of Nicaragua and a Counter-Memorial by the United States of America on the questions of jurisdiction and admissibility and these pleadings were duly filed within the time-limits fixed.

5.  In the Memorial, the Republic of Nicaragua contended that, in addition to the basis of jurisdiction relied on in the Application, a Treaty of Friendship, Commerce and Navigation signed by the Parties in 1956 provides an independent basis for jurisdiction under Article 36, paragraph 1, of the Statute of the Court.

6.  On 15 August 1984, prior to the closure of the written proceedings on the questions of jurisdiction and admissibility, the Republic of El Salvador filed a Declaration of Intervention in the case under Article 63 of the Statute.  In a letter from the Agent of El Salvador dated 10 September 1984, which El Salvador requested should be considered as a part of its Declaration of Intervention, El Salvador stated that, if the Court were to find that it has jurisdiction and that the Application is admissible, it reserved the right "in a later substantive phase of the case to address the interpretation and application of the conventions to which it is a party relevant to that phase".  Having been supplied with the written observations of the Parties on the Declaration pursuant to Article 83 of the Rules of Court, the Court, by an Order dated 4 October 1984, decided not to hold a hearing on the Declaration of Intervention, and decided that that Declaration was inadmissible inasmuch as it related to the current phase of the proceedings.

7.  On 8-10 and 15-18 October 1984 the Court held public sittings at which it was addressed by the following representatives of the Parties:
 
For Nicaragua: H.E. Mr. Carlos Arguello Gomez
Hon. Abram Chayes,
Mr. Ian Brownlie,
Mr. Paul S. Reichler,
Mr. Alain Pellet.
 
 For the United States of America: Hon. Davis R. Robinson,
 Mr. Patrick M. Norton,
 Mr. Myres McDougal,
 Mr. Louis B. Sohn,
 Mr. John Norton Moore.

8.  In the course of the written proceedings the following Submissions were presented by the Parties:
 
On behalf of Nicaragua, at the end of the Memorial: "Nicaragua submits that:

A.  The jurisdiction of the Court to entertain the dispute presented in the Application is established by the terms of the declaration of Nicaragua of 24 September 1929 under Article 36 (5) and the declaration of the United States of 14 August 1946 under Article 36 (2) of the Statute of the International Court of Justice.

B.  Nicaragua's declaration of 24 September 1929 is in force as a valid and binding acceptance of the compulsory jurisdiction of the Court.

C.  The attempt by the United States to modify or terminate the terms of its declaration of 14 August 1946 by a letter dated 6 April 1984 from Secretary of State George Shultz to the Secretary-General of the United Nations was ineffective to accomplish either result.

D.  The Court has jurisdiction under Article XXIV (2) of the Treaty of Friendship, Commerce and Navigation between the United States and Nicaragua of 24 May 1958 over claims presented by this Application falling within the scope of the Treaty.

E.  The Court is not precluded from adjudicating the legal dispute presented in the Application by any considerations of admissibility and the Application is admissible."
 
 On behalf of the United States of America,  
 at the end of the Counter-Memorial:

  "May it please the Court, on behalf of the United States of America, to adjudge and declare, for each and all of the foregoing reasons, that the  claims set forth in Nicaragua's Application of 9 April 1984 (1) are not within the jurisdiction of this Court and (2) are inadmissible."

9.  In the course of the oral proceedings the following Submissions were presented by the Parties:
 On behalf of Nicaragua
  (hearing of 10 October 1984):

"Maintaining the arguments and submissions contained in the Memorial presented on 30 June 1984 and also the arguments advanced in the oral hearings on behalf of Nicaragua:

The Government of Nicaragua requests the Court to declare that jurisdiction exists in respect of the Application of Nicaragua filed on 9 April 1984, and that the subject-matter of the Application is admissible in its entirety.  On behalf of the United States of America,
 
 (hearing of 16 October 1984):

"May it please the Court, on behalf of the United States of America, to adjudge and declare, for each and all of the reasons presented in the oral argument of the United States and in the Counter-Memorial of the United States of 17 August 1984, that the claims set forth in Nicaragua's Application of 9 April 1984, (1) are not within the jurisdiction of the Court and (2) are inadmissible."

10.  In accordance with Article 60, paragraph 2, of the Rules of Court, the two Parties communicated to the Court the written text of their final submissions as set out above.

* * *

11.  The present case concerns a dispute between the Government of the Republic of Nicaragua and the Government of the United States of America occasioned, Nicaragua contends, by certain military and paramilitary activities conducted in Nicaragua and in the waters off its coasts. responsibility for which is attributed by Nicaragua to the United States.  In the present phase the case concerns the jurisdiction of the Court to entertain and pronounce upon this dispute, and the admissibility of the Application by which it was brought before the Court.  The issue being thus limited, the Court will avoid not only all expressions of opinion on matters of substance, but also any pronouncement which might prejudge or appear to prejudge any eventual decision on the merits.

12.  To found the jurisdiction of the Court in the present proceedings. Nicaragua in its Application relied on Article 36 of the Statute of the Court and the declarations, described below, made by the Parties accepting compulsory jurisdiction pursuant to that Article.  In its Memorial, Nicaragua, relying on a reservation contained in its Application (para. 26) of the right to "supplement or to amend this Application", also contended that the Court has jurisdiction under Article XXIV, paragraph 2, of a Treaty of Friendship, Commerce and Navigation between the Parties signed at Managua on 21 January 1956.

13.  Article 36. paragraph 2, of the Statute of the Court provides that: "The States parties to the present Statute may at any time declare that they recognize as compulsory ipso facto and without special agreement, in relation to any other State accepting the same obligation, the jurisdiction of the Court in all legal disputes concerning:
 
(a) the interpretation of a treaty:
(b) any question of international law:
(c) the existence of any fact which. if established. would constitute a breach of an international obligation:
(d) the nature or extent of the reparation to be made for the breach of an international obligation."
 
The United States made a declaration. pursuant to this provision, on 14 August 1946, containing certain reservations, to be examined below, and expressed to "remain in force for a period of five years and thereafter until the expiration of six months after notice may be given to terminate this declaration".
 
On 6 April 1984 the Government of the United States of America deposited with the Secretary-General of the United Nations a notification, signed by the United States Secretary of State, Mr. George Shultz, referring to the Declaration deposited on 26 August 1946. and stating that: "the aforesaid declaration shall not apply to disputes with any Central American State or arising out of or related to events in Central America, any of which disputes shall be settled in such manner as the parties to them may agree.

Notwithstanding the terms of the aforesaid declaration, this proviso shall take effect immediately and shall remain in force for two years, so as to foster the continuing regional dispute settlement process which seeks a negotiated solution to the interrelated political, economic and security problems of Central America." This notification will be referred to, for convenience, as the "1984 notification".

14.  In order to be able to rely upon the United States Declaration of 1946 to found jurisdiction in the present case.  Nicaragua has to show that it is a "State accepting the same obligation" within the meaning of Article 36, paragraph 2, of the Statute.  For this purpose, Nicaragua relies on a Declaration made by it on 24 September 1929 pursuant to Article 36, paragraph 2, of the Statute of the Permanent Court of International Justice.  That Article provided that: "The Members of the League of Nations and the States mentioned in the Annex to the Covenant may, either when signing or ratifying the Protocol to which the present Statute is adjoined, or at a later moment, declare that they recognize as compulsory ipso facto and without special agreement, in relation to any other Member or State accepting the same obligation, the jurisdiction of the Court" in any of the same categories of dispute as listed in paragraph 2 of Article 36 of the Statute of the postwar Court, set out above.  Nicaragua relies further on paragraph 5 of Article 36 of the Statute of the present Court, which provides that: "Declarations made under Article 36 of the Statute of the Permanent Court of International Justice and which are still in force shall be deemed, as between the parties to the present Statute, to be acceptances of the compulsory jurisdiction of the International Court of Justice for the period which they still have to run and in accordance with their terms."

15. The circumstances of Nicaragua's Declaration of 1929 were as follows. The Members of the League of Nations (and the States mentioned in the Annex to the League of Nations Covenant) were entitled to sign the Protocol of Signature of the Statute of the Permanent Court of International Justice, which was drawn up at Geneva on 16 December 1920.  That Protocol provided that it was subject to ratification, and that instruments of ratification were to be sent to the Secretary-General of the League of Nations.  On 24 September 1929, Nicaragua, as a Member of the League, signed this Protocol and made a declaration under Article 36, paragraph 2, of the Statute of the Permanent Court which read:

[Translation from the French]
"On behalf of the Republic of Nicaragua I recognize as compulsory unconditionally the jurisdiction of the Permanent Court of International Justice.
Geneva, 24 September 1929.
(Signed) T. F. MEDINA."

16.  According to the documents produced by both Parties before the Court, on 4 December 1934, a proposal for the ratification of (inter alia) the Statute of the Permanent Court of International Justice and of the Protocol of Signature of 16 December 1920 was approved by the "Ejecutivo " (executive power) of Nicaragua.  On 14 February 1935, the Senate of Nicaragua decided to ratify these instruments, its decision being published in La Gaceta, the Nicaraguan official journal, on 12 June 1935, and on 11 July 1935 the Chamber of Deputies of Nicaragua adopted a similar decision, similarly published on 18 September 1935. On 29 November 1939, the Ministry of External Relations of Nicaragua sent the following telegram to the Secretary-General of the League of Nations:

" ESTATUTO Y PROTOCOLO CORTE PERMANENTE JUSTICIA INTERNACIONAL LA HAYA YA FUERON RATIFICADOS PUNTO ENVIARSELE OPORTUNAMENTE INSTRUMENTO RATIFICACION-RELACIONES."    [Translation]
(Statute and Protocol Permanent Court International Justice The Hague have already been ratified.  Will send you in due course Instrument Ratification Relations.)
 
 The files of the League of Nations however contain no record of an instrument of ratification ever having been received.  No evidence has been adduced before the Court to show that such an instrument of ratification was ever despatched to Geneva.  On 16 December 1942, the Acting Legal Adviser of the Secretariat of the League of Nations wrote to the Foreign Minister of Nicaragua to point out that he had not received the instrument of ratification "dont le depot est necessaire pour faire naitre effectivement l'obligation" (the deposit of which is necessary to cause the obligation to come into effective existence).  In the Nicaraguan Memorial, it was stated that "Nicaragua never completed ratification of the old Protocol of Signature"; at the hearings, the Agent of Nicaragua explained that the records are very scanty, and he was therefore unable to certify the facts one way or the other.  He added however that if instruments of ratification were sent, they would most likely have been sent by sea, and, the Second World War being then in progress, the attacks on commercial shipping may explain why the  instruments appear never to have arrived.  After the war, Nicaragua took part in the United Nations Conference on International Organization at San Francisco and became an original Member of the United Nations, having ratified the Charter on 6 September 1945; on 24 October 1945 the Statute of the International Court of Justice, which is an integral part of the Charter came into force.

17.  On We basis of these facts, the United States contends, first, that Nicaragua never became a party to the Statute of the Permanent Count of International Justice, and that accordingly it could not and did not make an effective acceptance of the compulsory jurisdiction of the Permanent Court; the 1929 acceptance was therefore not "still in force" within the meaning of the English version of Article 36, paragraph 5, of the Statute of the present Court. In the contention of the United States, the expression in the French version of the Statute corresponding to "still in force" in the English text, namely "pour une duree qui n'est pas encore expiree", also requires that a declaration be binding under the Statute of the Permanent Court in order to be deemed an acceptance of the jurisdiction of the present Court under Article 36, paragraph 5, of its Statute.

18.  Nicaragua does not contend that its 1929 Declaration was in itself sufficient to establish a binding acceptance of the compulsory jurisdiction of the Permanent Court of International Justice, for which it would have been necessary that Nicaragua complete the ratification of the Protocol of Signature of the Statute of that Court.  It rejects however the interpretation of Article 36, paragraph 5, of the Statute of the present Court advanced by the United States: Nicaragua argues that the phrase "which are still in force" or "pour une duree qui n'est pas encore expiree" was designed to exclude from the operation of the Article only declarations that had already expired, and has no bearing whatever on a declaration, like Nicaragua's that had not expired, but which, for some reason or another had not been perfected.  Consistently with the intention of the provision, which in Nicaragua's view was to continue the pre-existing situation as regards declarations of acceptance of compulsory jurisdiction, Nicaragua was in exactly the same situation under the new Statute as it was under the old.  In either case, ratification of the Statute of the Court would perfect its Declaration of 1929.  Nicaragua contends that the fact that this is the correct interpretation of the Statute is home out by the way in which the Nicaraguan declaration was handled in the publications of the Court and of the United Nations Secretariat; by the conduct of the Parties to the present case, and of the Government of Honduras, in relation to the dispute in 1957-1960 between Honduras and Nicaragua in connection with the arbitral award made by the King of Spain in 1906, which dispute was eventually determined by the Court; by the opinions of publicists; and by the practice of the United States itself.

19.  With regard to Nicaragua's reliance on the publications of the Court, it may first be noted that in the Sixteenth Report (the last) of the Permanent Court of International Justice, covering the period 15 June 1939 to 31 December 1945, Nicaragua was included in the "List of States having signed the Optional Clause" (p. 358), but it was recorded on another page (p. 50) that Nicaragua had not ratified the Protocol of Signature of the Statute, and Nicaragua was not included in the list of "States bound by the Clause" (i.e., the Optional Clause) on the same page. The first Yearbook, that for 1946-1947, of the present Court contained (p. 110) a list entitled "Members of the United Nations, other States parties to the Statute and States to which the Court is open.  (An asterisk denotes a State bound by the compulsory jurisdiction clause)", and Nicaragua was included in that list, with an asterisk against it, and with a footnote  (common to several States listed) reading "Declaration made under Article 36 of the Statute of the Permanent Court and deemed to be still in force (Article 36, 5, of Statute of the present Court)".  On another page (p. 210), the text of Nicaragua's 1929 Declaration was reproduced, with the following footnote: "According to a telegram dated November 29th, 1939, addressed to the League of Nations, Nicaragua had ratified the Protocol of Signature of the Statute of the Permanent Court of International Justice (December 16th, 1920), and the instrument of ratification was to follow.  Notification concerning the deposit of the said instrument has not, however, been received in the Registry." The Yearbook 1946-1947 also includes a list (p. 221) entitled "List of States which have recognized the compulsory jurisdiction of the International Court of Justice or which are still bound by their acceptance of the Optional Clause of the Statute of the Permanent Court of International Justice (Article 36 of the Statute of the International Court of Justice)" and this list includes Nicaragua (with a footnote cross-reference to the page where its 1929 Declaration is reproduced).

20.  Subsequent Yearbooks of the Court, up to and including I.C.J. Yearbook 1954-1955, list Nicaragua among the States with regard to which there were "in force" declarations of acceptance of the compulsory jurisdiction of the Court, made in accordance with the terms either of the Permanent Court of International Justice Statute or of the Statute of the present Court (see, e.g., Yearbook 1954-1955, p. 39); however, a reference was also given to the page of the Yearbook 1946-1947 at which the text of Nicaragua's 1929 Declaration was printed (ibid., p. 187).  Nicaragua also continued to be included in the list of States recognizing compulsory jurisdiction (ibid, p. 195).  In the Yearbook 1955-1956, the reference to Nicaragua in this list (p. 195) had a footnote appended to it reading as follows: "According to a telegram dated November 29th, 1939, addressed to the League of Nations, Nicaragua had ratified the Protocol of Signature of the Statute of the Permanent Court of International Justice (December 16th, 1920), and the instrument of ratification was to follow.  It does not appear, however, that the instrument of ratification was ever received by the League of Nations." A note to the same effect has been included in subsequent Yearbooks up to the present time.

21.  In 1968 the Court began the practice, which has continued up to the present time, of transmitting a Report to the General Assembly of the United Nations for the past year.  Each of these Reports has included a paragraph recording the number of States which recognize the jurisdiction of the Court as compulsory, and Nicaragua has been mentioned among these.  For a number of years the paragraph referred to such States as having so recognized the Court's jurisdiction "in accordance with declarations filed under Article 36, paragraph 2, of the Statute".  No reference has been made in these Reports to the issue of ratification of the Protocol of Signature of the Statute of the Permanent Court.

22.  Nicaragua also places reliance on the references made to it in a number of publications issued by the Secretariat of the United Nations, all of which include it as a State whose declaration of acceptance of the jurisdiction of the Permanent Court has attracted the operation of Article 36, paragraph 5, of the Statute of the present Court.  These publications are  the Second Annual  Report of the Secretary-General to the General Assembly; the annual volume entitled Signatures, Ratifications, Acceptances, Accessions, etc., concerning the Multilateral Conventions and Agreements in respect of which the Secretary-General acts as Depositary; the Yearbook of the United Nations; and certain ancillary official publications.

23.  The United States contention as to these publications is, as to those issued by the Registry of the Court, that the Registry took great care not to represent any of its listings as authoritative; the United States draws attention to the caveat in the Preface to the I.C.J. Yearbook that it "in no way involves the responsibility of the Court", to the footnotes quoted in paragraphs 19 and 20 above, and to a disclaimer appearing for the first time in the Yearbook 1956-1957 (p. 207) reading as follows: "The texts of declarations set out in this Chapter are reproduced for convenience of reference only.  The inclusion of a declaration made by any State should not be regarded as an indication of the view entertained by the Registry or, afortiori, by the Court, regarding the nature, scope or validity of the instrument in question."  It concludes that it is clear that successive Registrars and the Yearbooks of the Court never adopted, and indeed expressly rejected, Nicaragua's contention as to the effect of Article 36, paragraph 5, of the Statute.  So far as the United Nations publications are concerned, the United States points out that where they cite their source of information, they invariably refer to the I.C.J. Yearbook, and none of them purport to convey any authority.

*

24.  In order to determine whether the provisions of Article 36, paragraph 5, can have applied to Nicaragua's Declaration of 1929, the Court must first establish the legal characteristics of that declaration and then compare them with the conditions laid down by the text of that paragraph.

25.  So far as the characteristics of Nicaragua's declaration are concerned, the Court notes that, at the time when the question of the applicability of the new Statute arose, that is, on its coming into force, that declaration was certainly valid, for under the system of the Permanent Court of International Justice a declaration was valid on condition that it had been made by a State "either when signing or ratifying" the Protocol of Signature of the Statute "or at a later moment", whereas under the present Statute, declarations under Article 36, paragraph 2, can only be made by "States parties to the present Statute".  Since Nicaragua had signed that Protocol, its declaration concerning the compulsory jurisdiction of the Permanent Court, which was not subject to ratification, was undoubtedly valid from the moment it was received by the Secretary-General of the League of Nations (cf. Right of Passage over Indian Territory, I.C.J. Reports 1957, p. 146).  The Statute of the Permanent Court did not lay down any set form or procedure to be followed for the making of such declarations, and in practice a number of different methods were used by States. Nevertheless this declaration, though valid, had not become binding under the Statute of the Permanent Court.  It may be granted that the necessary steps had been taken at national level for ratification of the Protocol of Signature of the Statute.  But Nicaragua has both been able to prove that it accomplished the indispensable step of sending its instrument of ratification to the Secretary-General of the League of Nations.  It did announce that the  instrument would be sent: but there is no evidence to show whether it was. Even after having been duly informed, by the Acting Legal Adviser of the League of Nations Secretariat, of the consequences that this might have upon its position vis-a-vis the jurisdiction of the Permanent Court, Nicaragua failed to take the one step that would have easily enabled it to be counted beyond question as one of the States that had recognized the compulsory jurisdiction of the Permanent Court of International Justice. Nicaragua has in effect admitted as much.

26.  The Court therefore notes that Nicaragua, having failed to deposit its instrument of ratification of the Protocol of Signature of the Statute of the Permanent Court, was not a party to that treaty.  Consequently the Declaration made by Nicaragua in 1929 had not acquired binding force prior to such effect as Article 36, paragraph 5, of the Statute of the International Court of Justice might produce.

27.  However, while the declaration had not acquired binding force, it is not disputed that it could have done so, for example at the beginning of 1945, if Nicaragua had ratified the Protocol of Signature of the Statute of the Permanent Court.  The correspondence brought to the Court's attention by the Parties, between the Secretariat of the League of Nations and various Governments including the Government of Nicaragua, leaves no doubt as to the fact that, at any time between the making of Nicaragua's declaration and the day on which the new Court came into existence, if not later, ratification of the Protocol of Signature would have sufficed to transform the content of the 1929 Declaration into a binding commitment; no one would have asked Nicaragua to make a new declaration.  It follows that such a declaration as that made by Nicaragua had a certain potential effect which could be maintained indefinitely.  This durability of otential effect flowed from a certain characteristic of Nicaragua's declaration: being made "unconditionally", it was valid for an unlimited period.  Had it provided, for example, that it would apply for only five years to disputes arising after its signature, its potential effect would admittedly have disappeared as from 24 September 1934.  In sum, Nicaragua's 1929 Declaration was valid at the moment when Nicaragua became a party to the Statute of the new Court; it had retained its potential effect because Nicaragua, which could have limited the duration of that effect, had expressly refrained from doing so.

28.  The characteristics of Nicaragua's declaration to move now to be compared with the conditions of applicability of Article 36, paragraph 5, as laid down in that provision.  The first condition concerns the relationship between the declarations and the Statute.  Article 36, paragraph 5, refrains from stipulating that declarations must have been made by States parties to the Statute of the Permanent Court: it is sufficient for them to have been made "under" (in French, "en application de") Article 36 of that Statute. But those who framed the new text were aware that under that Article, a State could make such a declaration "either when signing or ratifying the Protocol . . . or at a later moment", i.e., that a State could make a declaration when it had not ratified the Protocol of Signature of the Statute, but only signed it.  The chosen wording therefore does not exclude but, on the contrary, covers a declaration made in the circumstances of Nicaragua's declaration.  Apart from this relationship with the Statute of the Permanent Court, the only condition which declarations have to fulfil is that they should be "still in force" (in English) or "faites pour une duree qui nest pas encore expirie" (in French). The Parties have devoted much argument to this apparent discrepancy between the two versions, its real meaning and the interpretation which the Court should  adopt as correct.  Drawing opposite conclusions from the jurisprudence of the Court, as contained in particular in the case concerning the Aerial Incident of 27 July 1955 (Israel v. Bulgaria), they have expatiated on the respective arguments by which, they allege, it supports their own case.

29.  The Court must in the first place observe that this is the first time that it has had to take a position on the question whether a declaration which did not have binding force at the time of the Permanent Court is or is not to be numbered among those to which Article 36, paragraph 5, of the Statute of the International Court of Justice applies.  The case of the Aerial Incident of 27 July 1955 featured quite a different issue -- in a nutshell, whether the effect of a declaration that had unquestionably become binding at the time of the Permanent Court could be transposed to the International Court of Justice when the declaration in question had been made by a State which had not been represented at the San Francisco Conference and had not become a party to the Statute of the present Court until long after the extinction of the Permanent Court.  In view of this difference in the issues, the Court does not consider that its decision in the Aerial Incident case, whatever may be its relevance in other respects, provides any pointers to precise conclusions on the limited point now in issue.  The most that could be pointed out on the basis of the discussions surrounding the Aerial Incident case is that, at that time, the United States took a particularly broad view of the separability of an Optional-Clause declaration and its institutional foundation by contending that an Optional-Clause declaration (of a binding character) could have outlived by many years the court to which it related.  But the present case also involves a problem of separability, since the question to be decided is the extent to which an Optional-Clause declaration (without binding force) can be separated from the institutional foundation which it ought originally to have possessed, so as to be grafted onto a new institutional foundation.

30.  Having thus stressed the novelty of the problem, the Court will refer to the following considerations in order to reach a solution.  First, it does not appear possible to reconcile the two versions of Article 36, paragraph 5, by considering that both versions refer to binding declarations.  According to this interpretation, upheld by the United States, Article 36, paragraph 5, should be read as if it mentioned "binding" declarations.  The French text, in this view, would be the equivalent of the English text, for logically it would imply that declarations dont la duree nest pas encore expirie are solely those which have acquired binding force.  The Court, however, considers that it must interpret Article 36, paragraph 5, on the basis of the actual terms used, which do not include the word "binding".  According to the travaux preparatoires the word "binding" was never suggested; and if it had been suggested for the English text, there is no doubt that the drafters would never have let the French text stand as finally worded.  Furthermore, the Court does not consider the French text to imply that la duree non expiree (the unexpired period) is that of a commitment of a binding character.  It may be granted that, for a period to continue or expire, it is necessary for some legal effect to have come into existence.  But this effect does not necessarily have to be of a binding nature. A declaration validly made under Article 36 of the Statute of the Permanent Court had a certain validity which could be preserved or destroyed, and it is perfectly possible to read the French text as implying only this validity.

31.  Secondly, the Court cannot but be struck by the fact that the French Delegation at the San Francisco Conference called for the expression "still in force" to be translated, not by "encore en vigueur" but by the term: pour une  duree qui nest pas encore expiree".  In view of the excellent equivalence of the expressions "encore en vigueur" and "still in force", the deliberate choice of the expression "pour une duree qui nest pas encore expiree" seems to denote an intention to widen the scope of Article 36, paragraph 5, so as to cover declarations which have not acquired binding force.  Other interpretations of this proposal are not excluded, but it may be noted that both "encore en vigueur" and "pour une duree qui nest pas encore expiree" would exclude a declaration, like that of France, which had been binding but which had expired by lapse of time.  It can only be said, on the other hand, that the English version does not require (any more than does the French version) that the declarations concerned should have been made by States parties to the Statute of the Permanent Court and does not mention the necessity of declarations having any binding character for the provision to be applicable to them.  It is therefore the Court's opinion that the English version in no way expressly excludes a valid  declaration of unexpired duration, made by a State not party to the Protocol of Signature of the Statute of the Permanent Court, and therefore not of a binding character.

32.  The Court will therefore, before deciding on its interpretation, have to examine to what extent the general considerations governing the transfer of the powers of the former Court to the new one, and thus serving to define the object and the purpose of the provisions adopted, throw light upon the correct interpretation of the paragraph in question.  As the Court has already had occasion to state in the case of the Aerial Incident of 27 July 1955 (Israel v. Bulgaria), the primary concern of those who drafted the Statute of the present Court was to maintain the greatest possible continuity between it and its predecessor.  As the Court then observed: "the clear intention which inspired Article 36, paragraph 5, was to continue in being something which was in existence, to preserve existing acceptances, to avoid that the creation of a new Court should frustrate progress already achieved" (I.C.J. Reports 1959, p. 145).

33.  In the present case, the Parties, in their pleadings and in the course of the hearings, have drawn attention to certain statements bearing witness to this general preoccupation; for example the report to his Government of the Chairman of the New Zealand delegation to the San Francisco Conference, who stressed that the primary concern had been "to maintain so far as possible the progress towards compulsory jurisdiction".  If, for a number of circumstantial reasons, it seemed necessary to abolish the former Court and to put the new one in its place, at least the delegates to the San Francisco Conference were determined to see that this operation should not result in a step backwards in relation to the progress accomplished towards adopting a system of compulsory jurisdiction.  That being so, the question is whether this intention sheds any light upon the present problem of interpretation of Article 36, paragraph 5.

34.  In this connection it is undeniable that a declaration by which a State recognizes the compulsory jurisdiction of the Court is "in existence", in the sense given above, and that each such declaration does constitute a certain progress towards extending to the world in general the system of compulsory judicial settlement of international disputes.  Admittedly, this progress has not yet taken the concrete form of a commitment having binding force, but nonetheless, it is by no means negligible.  There are no grounds for maintaining that those who drafted the Statute meant to go back on this progress and place it in a category in opposition to the progress achieved by declarations having  binding force.  No doubt their main aim was to safeguard these latter declarations, but the intention to wipe out the progress evidenced by a declaration such as that of Nicaragua would certainly not square well with their general concern.  As the Court said in the very similar matter of the already existing field of conventional compulsory jurisdiction, it was "a natural element of this compromise" (then accepted by comparison with the ideal of universal compulsory jurisdiction) "that the maximum, and not some merely quasi optimum preservation of this field should be aimed at" (Barcelona Traction, Light and Power Company, Limited, I.C.J. Reports 1964, p. 32).  Furthermore, if the highly experienced drafters of the Statute had had a restrictive intention on this point, in contrast to their overall concern, they would certainly have translated it into a very different formula from the one which they in fact adopted.

35.  On the other hand, the logic of a system substituting a new Court for the former one without the cause of compulsory jurisdiction in any way suffering in the process resulted in the ratification of the new Statute having exactly the same effects as the ratification of the Protocol of Signature of the former one would have had, that is to say, in the case of Nicaragua, the step from potential commitment to effective commitment. The general system of devolution from the old Court to the new thus lends support to the interpretation whereby Article 36, paragraph 5, even covers declarations that had not previously acquired binding force.  In this connection, it should not be overlooked that Nicaragua was represented at the San Francisco Conference, and duly signed and ratified the Charter of the United Nations.  At that time, the consent which it had given in 1929 to the jurisdiction of the Permanent Court had not become fully effective in the absence of ratification of the Protocol of Signature; but taking into account the interpretation given above, the Court may apply to Nicaragua what it stated in the case of the Aerial Incident of 27 July 1955:   "Consent to the transfer to the International court of Justice of a declaration accepting the jurisdiction of the Permanent Court may be regarded as effectively given by a State which, having been represented at the San Francisco Conference, signed and ratified the Charter and thereby accepted the Statute in which Article 36, paragraph 5, appears." (I.C.J. Reports 1959, p. 142.)

36.  This finding as regards the interpretation of Article 36, paragraph 5, must, finally, be compared to the conduct of States and international organizations in regard to this interpretation.  In that respect, particular weight must be ascribed to certain official publications, namely the I.C.J. Yearbook (since 1946-1947), the Reports of the Court to the General Assembly of the United Nations (since 1968) and the annually published collection of Signatures, Ratifications, Acceptances, Accessions, etc., concerning the Multilateral Conventions and Agreements in respect of which the Secretary-General acts as Depositary.  The Court notes that, ever since they first appeared, all these publications have regularly placed Nicaragua on the list of those States that have recognized the compulsory jurisdiction of the Court by virtue of Article 36, paragraph 5, of the Statute.  Even if the I.C.J. Yearbook has, in the issue for 1946-1947 and as from the issue for 1955-1956 onwards, contained a note recalling certain facts concerning Nicaragua's ratification of the Protocol of Signature of the Statute of the Permanent Court of International Justice, this publication has never modified  the classification of Nicaragua or the binding character attributed to its 1929 Declaration -- indeed the Yearbooks list Nicaragua among the States "still bound by" their declarations under Article 36 of the Statute of the Permanent Court  (see paragraph 19, above).  The same observation is valid for the Secretariat publication Signatures, Ratifications, Acceptances, Accessions, etc., which derived its data, including footnotes, from the I.C.J. Yearbook.  As for the reports of the Court, they are quite categorical in stating that Nicaragua had accepted compulsory jurisdiction, even if the distinction between acceptances made under Article 36, paragraph 2, and those "deemed" to be such acceptances, is not spelled out.

37.  The Court has no intention of assigning these publications any role that would be contrary to their nature but will content itself with noting that they attest a certain interpretation of Article 36, paragraph 5 (whereby that provision would cover the declaration of Nicaragua), and the rejection of an opposite interpretation (which would refuse to classify Nicaragua among the States covered by that Article).  Admittedly, this testimony concerns only the result and not the legal reasoning that leads to it. However, the inclusion of Nicaragua in the "List of States which have recognized the compulsory jurisdiction of the International Court of Justice, or which are still bound by their acceptance of the Optional Clause of the Statute of the Permanent Court of International Justice", as from the appearance of the first I.C.J. Yearbook (1946-1947), contrasts with its exclusion from the list in the last Report of the Permanent Court of International Justice of "States bound by the [optional] clause".  It is therefore difficult to escape the conclusion that the basis of this innovation was to be found in the possibility that a declaration which, though not of binding character, was still valid, and was so for a period that had not yet expired, permitted the application of Article 36, paragraph 5, so long as the State in question, by ratifying the Statute of the International Court of Justice, provided it with the institutional foundation that it had hitherto lacked.  From that moment on, Nicaragua would have become "bound" by its 1929 Declaration, and could, for practical purposes, appropriately be included in the same Yearbook list as the States which had been bound even prior to the coming into force of the post-war Statute.

38.  The importance of this lies in the significance to be attached to the conduct of the States concerned, which is dependent on the testimony thus furnished by these publications.  The point is not that the Court in its administrative capacity took a decision as to Nicaragua's status which would be binding upon it in its judicial capacity, since this clearly could not be so. It is that the listing found appropriate for Nicaragua amounted over the years to a series of attestations which were entirely official and public, and extremely numerous, and ranged over a period of nearly 40 years; and that hence the States concerned -- first and foremost, Nicaragua -- had every opportunity of accepting or rejecting the thus-proclaimed applicability of Article 36, paragraph 5, to the Nicaraguan Declaration of 1929.

39.  Admittedly, Nicaragua itself, according to the information furnished to the Court, did not at any moment explicitly recognize that it was bound by its recognition of the Court's compulsory jurisdiction, but neither did it deny the existence of this undertaking.  The Court notes that Nicaragua, even if its conduct in the case concerning the Arbitral Award Made by the King of Spain on 23 December 1906 was not unambiguous, did not at any time declare that it was not bound by its 1929 Declaration. Having regard to the public and unchanging nature of the official statements concerning Nicaragua's commitment under the Optional-Clause system, the silence of its Government can only be interpreted as an acceptance of the classification thus assigned to it.  It cannot be supposed that that Government could have believed that its silence could be tantamount  to anything other than acquiescence.  Besides, the Court would remark that if proceedings had been instituted against Nicaragua at any time in these recent years, and it had sought to deny that, by the operation of Article 36, paragraph 5, it had recognized the compulsory jurisdiction of the Court, the Court would probably have rejected that argument.  But the Court's jurisdiction in regard to a particular State does not depend on whether that State is in the position of an Applicant or a Respondent in the proceedings.  If the Court considers that it would have decided that Nicaragua would have been bound in a case in which it was the Respondent, it must conclude that its jurisdiction is identically established in a case where Nicaragua is the Applicant.

40.  As for States other than Nicaragua, including those which could be supposed to have the closest interest in that State's legal situation in regard to the Court's jurisdiction, they have never challenged the interpretation to which the publications of the United Nations bear witness and whereby the case of Nicaragua is covered by Article 36, paragraph 5.  Such States as themselves publish lists of States bound by the compulsory jurisdiction of the Court have placed Nicaragua on their lists.  Of course, the Court is well aware that such national publications simply reproduce those of the United Nations where that particular point is concerned.  Nevertheless, it would be difficult to interpret the fact of such reproduction as signifying an objection to the interpretation thus given; on the contrary, this reproduction contributes to the generality of the opinion which appears to have been cherished by States parties to the Statute as regards the applicability to Nicaragua of Article 36, paragraph 5.

41.  Finally, what States believe regarding the legal situation of Nicaragua so far as the compulsory jurisdiction of the Court is concerned may emerge from the conclusions drawn by certain governments as regards the possibility of obliging Nicaragua to appear before the Court or of escaping any proceedings it may institute.  The Court would therefore recall that in the case concerning the Arbitral Award Made by the King of Spain on 23 December 1906 Honduras founded its application both on a special agreement, the Washington Agreement, and on Nicaragua's Optional-Clause declaration.  It is also difficult for the court not to consider that the United States letter of 6 April 1984 implies that at that date the United States, like  other States, believed that Nicaragua was bound by the Court's jurisdiction in accordance with the terms of its 1929 Declaration.

42.  The Court thus finds that the interpretation whereby the provisions of Article 36, paragraph 5, cover the case of Nicaragua has been confirmed by the subsequent conduct of the parties to the treaty in question, the Statute of the Court.  However, the conduct of States which has been considered has been in relation to publications of the Court and of the United Nations Secretariat which, as noted in paragraph 37 above, do not indicate the legal reasoning leading to the conclusion that Nicaragua fell within the category of States to whose declarations Article 36, paragraph 5, applied.  The view might have been taken that that paragraph applied because the Nicaraguan telegram of 29 November 1929 in itself constituted ratification of the Protocol of Signature.  It should therefore be observed that the conduct of Nicaragua in relation to the publications in question also supports a finding of jurisdiction under Article 36, paragraph 2, of the Statute independently of the interpretation and effect of paragraph 5 of that Article.

43.  Nicaragua has in fact also contended that the validity of Nicaragua's recognition of the compulsory jurisdiction of the Court finds an independent basis in the conduct of the Parties.  The argument is that Nicaragua's conduct  over a period of 38 years unequivocally constitutes consent to be bound by the compulsory jurisdiction of the Court by way of a recognition of the application of Article 36, paragraph 5, of the Statute to the Nicaraguan Declaration of 1929.  Likewise the conduct of the United States over a period of 38 years unequivocally constitutes its recognition of the essential validity of the Declaration of Nicaragua of 1929 as a result of the application of Article 36, paragraph 5, of the Statute.  As a consequence it was recognized by both Parties that any formal defect in Nicaragua's ratification of the Protocol of Signature of the Statute of the Permanent Court did not in any way affect the essential validity of Nicaragua's consent to the compulsory jurisdiction.  The essential validity of the Nicaraguan declaration as an acceptance of the compulsory jurisdiction is confirmed by the evidence of a long series of public documents, by the general opinion of States and by the general opinion of qualified publicists.

44.  The United States however objects that this contention of Nicaragua is flatly inconsistent with the Statute of the Court, which provides only for consent to jurisdiction to be manifested in specified ways; an "independent title of jurisdiction, as Nicaragua calls it, is an impossibility".  The Statute provides the sole bases on which the Court can exercise jurisdiction, under Articles 36 and 37.  In the particular case of Article 36, paragraph 5, the Statutes of the two Courts provide a means for States to express their consent, and Nicaragua did not use them.  The United States urges what it describes as policy considerations of fundamental importance: that compulsory jurisdiction, being a major obligation, must be based on the clearest manifestation of the State's intent to accept it: that Nicaragua's thesis introduces intolerable uncertainty into the system; and that that thesis entails the risk of consenting to compulsory jurisdiction through silence, with all the harmful consequences that would ensue.  The United States also disputes the significance of the publications and conduct on which Nicaragua bases this contention.

45.  The Court would first observe that, as regards the requirement of consent as a basis of its jurisdiction, and more particularly as regards the formalities required for that consent to be expressed in accordance with the provisions of Article 36, paragraph 2, of the Statute, the Court has already made known its view in, inter alia, the case concerning the Temple of Preah Vihear.  On that occasion it stated: "The only formality required is the deposit of the acceptance with the Secretary-General of the United Nations under paragraph 4 of Article 36 of the Statute." (I.C.J. Reports 1961, p. 31.)

46.  The Court must enquire whether Nicaragua's particular circumstances afford any reason for it to modify the conclusion it then reached. After all, the reality of Nicaragua's consent to be bound by its 1929 Declaration is, as pointed out above, attested by the absence of any protest against the legal situation ascribed to it by the publications of the Court, the Secretary-General of the United Nations and major States.  The question is therefore whether, even if the consent of Nicaragua is real, the Court can decide that it has been given valid expression even on the hypothesis that the 1929 Declaration was without validity, and given that no other declaration has been deposited by Nicaragua since it became a party to the Statute of the International Court of Justice. In this connection the Court notes that Nicaragua's situation has been wholly unique, in that it was the publications of the Court itself (since 1947, the I.C.J. Yearbook; since 1968, the Reports to the General Assembly of the United Nations), and those of the Secretary-General (as depositary of the declarations under the Statute of the present Court) which affirmed (and still affirm  today, for that matter) that Nicaragua had accomplished the formality in question. Hence, if the Court were to object that Nicaragua ought to have made a declaration under Article 36, paragraph 2, it would be penalizing Nicaragua for having attached undue weight to the information given on that point by the Court and the Secretary-General of the United Nations and, in sum, having (on account of the authority of their sponsors) regarded them as more reliable than they really were.

47.  The Court therefore recognizes that, so far as the accomplishment of the formality of depositing an optional declaration is concerned, Nicaragua was placed in an exceptional position, since the international organs empowered to handle such declarations declared that the formality in question had been accomplished by Nicaragua.  The Court finds that this exceptional situation cannot be without effect on the requirements obtaining as regards the formalities that are indispensable for the consent of a  State to its compulsory jurisdiction to have been validly given.  It considers therefore that, having regard to the origin and generality of the statements to the effect that Nicaragua was bound by its 1929 Declaration, it is right to conclude that the constant acquiescence of that State in those affirmations constitutes a valid mode of manifestation of its intent to recognize the compulsory jurisdiction of the Court under Article 36, paragraph 2, of the Statute, and that accordingly Nicaragua is, vis-a-vis the United States, a State accepting "the same obligation" under that Article.

* * *

48.  The United States, however, further contends that even if Nicaragua is otherwise entitled to invoke against the United States the jurisdiction of the Court under Article 36, paragraphs 2 and 5, of the Statute, Nicaragua's conduct in relation to the United States over the course of many years estops Nicaragua from doing so.  Having, it is argued, represented to the United States that it was not itself bound under the system of the Optional Clause, Nicaragua is estopped from invoking compulsory jurisdiction under that clause against the United States.  The United States asserts that since 1943 Nicaragua has consistently represented to the United States of America that Nicaragua was not bound by the Optional Clause, and when the occasion arose that this was material to the United States diplomatic activities, the United States relied upon those Nicaraguan representations.

49.  The representations by Nicaragua relied on by the United States were as follows.  First, in 1943, the United States Ambassador to Nicaragua consulted the Nicaraguan Foreign Minister on the question whether the Protocol of Signature of the Statute of the Permanent Court had been ratified by Nicaragua. According to a despatch from the Ambassador to Washington, a decree of July 1935 signed by the President of Nicaragua, mentioning the approval of the ratification by the Senate and Chamber of Deputies, was traced, as was a copy of the telegram to the Secretariat of the League of Nations dated 29 November 1939 (see paragraph 16, above). The decree stated that it was to become effective on the date of its publication in La Gaceta.  The Ambassador informed his Government that: "The Foreign Minister informs me that the decree was never published in La Gaceta.  He also declared that there is no record to the instrument of ratification having been transmitted to Geneva.  I would appear that, while appropriate legislative action was taken in Nicaragua to approve adherence to  the Protocol, Nicaragua is not legally bound thereby, in as much as it did not deposit its official document of ratification with the League of Nations."  According to the United States, the United States and Nicaragua could only have understood at that point in time that Nicaragua was not bound by the Optional Clause, and that understanding never changed.

50.  Secondly, in 1955-1958 there was diplomatic contact between Honduras, Nicaragua and the United States our the dispute which was eventually determined by the Court as the case of the Arbitral Award Made by the King of Spain on 23 December 1906 (I.C.J. Reports 1960, p. 192).  One of the questions then under examination was whether Honduras would be entitled to institute proceedings against Nicaragua in reliance upon the 1929 Declaration and Article 36, paragraph 5, of the Statute, and in this connection the Government of Honduras requested the good offices of the Government of the United States.  In a conversation between the Nicaraguan Ambassador in Washington and United States officials on 21 December 1955, "reference was made to the fact that the matter had not been previously referred to the Court because Nicaragua had never agreed to submit to compulsory jurisdiction", and the Ambassador was recorded to have "indicated that an agreement between the two countries would have to be reached to overcome this difficulty".  The United States interprets this as a statement of Nicaragua's understanding that it was not bound by the Optional Clause. Further, on 2 March 1956 the Ambassador is alleged to have observed that there was "some doubt as to whether Nicaragua would be officially obligated to submit to the International Court because an instrument of ratification of the Court's jurisdiction was never sent". It is contended that the United States relied on these representations by Nicaragua; the United States has produced documents to support the claims that the entire premise of United States diplomatic efforts was that Nicaragua was not a party to the Optional Clause, and observes that in the eventual proceedings before the Court between Nicaragua and Honduras, Nicaragua manifested its hostility to the compulsory jurisdiction of the Court.  Nicaragua has made no deal reply to the United States argument of estoppel, which was only fully developed during the oral proceedings; however, the position of Nicaragua as to its own conduct is, as indicated above, that so far from having represented that it was not bound by the Optional Clause, on the contrary its conduct unequivocally constituted consent to be so bound.

51.  For the same reason, the Court does not need to deal at length with the contention based on estoppel.  The Court has found that the conduct of Nicaragua, having regard to the very particular circumstances in which it was placed, was such as to evince its consent to be bound in such a way as to constitute a valid mode of acceptance of jurisdiction (paragraph 47, above).  It is thus evident that the Court cannot regard the information obtained by the United States in 1943, or the doubts expressed in diplomatic contracts in 1955, as sufficient to overturn that conclusion, let alone to support an estoppel. Nicaragua's contention that since 1946 it has consistently maintained that it is subject to the jurisdiction of the Court, is  supported by substantial evidence. Furthermore, as the Court pointed out in the North Sea Continental Shelf cases (I.C.J. Reports 1969, p. 26), estoppel may be inferred from the conduct, declarations and the like made not only dearly and consistently evinced acceptance by that State of a particular regime, but also had caused another  State or States, in reliance on such conduct, detrimentally to change position or suffer some prejudice.  The Court cannot regard Nicaragua's reliance on the optional clause as in any way contrary to good faith or equity: nor can Nicaragua be taken to come within the criterion of the North Sea Continental Shelf case, and the invocation of estoppel by the United States of America cannot be said to apply to it.

* * *

52.  The acceptance of jurisdiction by the United States which is relied on by Nicaragua is, as noted above, that dated 14 August 1946.  The United States contends however that effect must also be given to the "1984 notification" -- the declaration deposited with the Secretary-General of the United Nations on 6 April 1984.  It is conceded by Nicaragua that if this declaration is effective as a modification or termination of the Declaration of 14 August 1946, and valid as against Nicaragua at the date of its filing of the Application instituting the present proceedings (9 April 1984), then the Court is without jurisdiction to entertain those proceedings, at least under Article 36, paragraphs 2 and 5, of the Statute.  It is however contended by Nicaragua that the 1984 notification is ineffective because international law provides no basis for unilateral modification of declarations made under Article 36 of the Statute of the Court, unless a right to do so has been expressly reserved.

53.  The United States insists that the effect of the 1984 notification was a modification and not a termination of its 1946 Declaration.  It argues that, notwithstanding the fact that its 1946 Declaration did not expressly reserve a right of modification (as do the declarations made under Article 36 by a number of other States), the 1984 notification effected a valid modification of the 1946 Declaration temporarily suspending the consent of the United States to the adjudication of the claims of Nicaragua.  For the United States, declarations under Article 36 are sui generis, are not treaties, and are not governed by the law of treaties, and States have the sovereign right to qualify an acceptance of the Court's compulsory jurisdiction, which is an inherent feature of the Optional-Clause system as reflected in, and developed by, State practice.  It is suggested that the Court has recognized the existence of an inherent, extra-statutory, right to modify declarations in any manner not inconsistent with the Statute at any time until the date of filing of an Application.  The United States also draws attention to the fact that its declaration dates from 1946, since when, it asserts, fundamental changes have occurred in State practice under the Optional Clause, and argues that to deny a right of modification to a State which had,in such an older declaration, not expressly reserved such a right would be inequitable and unjustified in the light of those changes in State practice.

54.  Nicaragua argues further, in the alternative, that the 1984 notification may be construed as a purported termination of the United States Declaration of 1946 and, in effect, the substitution of a new declaration, and that such an attempt at termination is likewise ineffective.  As noted in paragraph 13 above, the 1946 Declaration was to remain in force "for a period of five years and thereafter until the expiration of six months after notice may be given to terminate this declaration".  Accordingly, if the 1984 notification constituted a termination of the 1946 Declaration (whether or not accompanied in effect by the making of a revised declaration) it could only take effect on 6 October 1984, and was as yet ineffective when the Application of Nicaragua was filed on 9 April 1984.  Both Parties apparently recognize that a modification of a  declaration which only takes effect after the Court has been validly seised does not affect the Court's jurisdiction: as the Court found in the Nottebohm case, "Once the Court has been regularly seised, the Court must exercise its powers, as these are defined in the Statute.  After that, the expiry of this period fixed for one of the Declarations on which the Application was founded is an event which is unrelated to the exercise of the powers conferred on the Court by the Statute, which the Court must exercise whenever it has been regularly seised and whenever it has not been shown, on some other ground, that it lacks jurisdiction or that the claim is inadmissible" (I.C.J. Reports 1953, p. 122), and the same reasoning applies to a supervening withdrawal or modification of a declaration.

55.  The first answer given by the United States to this contention of Nicaragua is that the 1984 notification was, on its face, not a "termination", and the six months' notice proviso was accordingly inapplicable. However, in the view of the United States, even if it be assumed for the sake of argument that the six months' notice proviso was applicable to the 1984 notification, the modification made by that letter was effective vis-a-vis Nicaragua, even if not effective erga omnes.  As already explained, one contention of the United States in relation to its own Declaration of 1946 is that States have a sovereign, inherent, extra-statutory right to modify at any time declarations made under Article 36 of the Statute in any manner not inconsistent with the Statute (paragraph 53, above).  Similarly Nicaragua's 1929 Declaration, being indefinite in duration, not unlimited, is subject to a right of immediate termination, without previous notice by Nicaragua.  The United States, on the other hand, while enjoying the inherent right of unilateral modification of its declaration, has bound itself  by the proviso in its 1946 Declaration to terminate that declaration only on six months' notice.  On this basis, the United States argues that Nicaragua has not accepted "the same obligation" (for the purposes of Art. 36, para. 2, of the Statute) as the United States six months' notice proviso, and may not therefore oppose that proviso as against the United States. According to the United States contention, the principles of reciprocity, mutuality and equality of States before the Court permit the United States to exercise the right of termination with the immediate effect implicitly enjoyed by Nicaragua, regardless of the six months' notice proviso in the United States Declaration.  The United States does not claim on this ground to exercise such a right of immediate termination erga omnes, but it does claim to exercise it vis-a-vis Nicaragua.

56.  Nicaragua first denies that declarations under Article 36 are always inherently terminable; the general view is said to be that declarations which contain no provision for termination continue in force indefinitely, in contractual terms; the question how far they may be terminable is governed by the principles of the law of treaties applicable to consensual legal relations arising within the system of the Optional Clause.  Nicaragua concludes that its declaration was made without limit of time, and that there can be no legal justification for the view that it is subject to unilateral modification.  The thesis that Nicaragua has not accepted "the same obligation" as the United States is, Nicaragua suggests, completely baseless. So far as reciprocity is concerned, Nicaragua concludes from its examination of the views of publicists that reciprocity is ex hypothesi inapplicable to time-limits, as opposed to express reservations reserving the power to modify or terminate declarations, and that in respect of such express reservations reciprocity can only operate  when a specific act of modification or termination is notified by virtue of the express reservation.

57.  The terms of the 1984 notification, introducing substantial changes in the United States Declaration of Acceptance of 1946, have been quoted above; they constitute an important element for the development of the Court's reasoning.  The 1984 notification has two salient aspects: on the one hand it states that the 1946 Declaration of acceptance shall not apply to disputes with any Central American State or arising out of or related to events in Central America; on the other hand it states that it is to take effect immediately, notwithstanding the terms of the 1946 Declaration, and is to remain in force for two years.

58.  The argument between the Parties as to whether the 1984 notification should be categorized as a modification or as a termination of the 1946 Declaration appears in fact to be without consequence for the purpose of this Judgment.  The truth is that it is intended to secure a partial and temporary termination, namely to exempt, with immediate effect, the United States from the obligation to subject itself to the Court's jurisdiction with regard to any application concerning disputes with Central American States, and disputes arising out of events in Central America. Counsel for the United States during the hearings claimed that the notification was equally valid against Nicaragua whether it was regarded as a "modification" or as a "termination" of the Acceptance Declaration.

59.  Declarations of acceptance of the compulsory jurisdiction of the Court are facultative, unilateral engagements, that States are absolutely free to make or not to make.  In making the declaration a State is equally free either to do so unconditionally and without limit of time for its duration, or to qualify it with conditions or reservations.  In particular, it may limit its effect to disputes arising after a certain date; or it may specify how long the declaration itself shall remain in force, or what notice (if any) will be required to terminate it.  However, the unilateral nature of declarations does not signify that the State making the declaration is free to amend the scope and the contents of its solemn commitments as it pleases. In the Nuclear Tests cases the Court expressed its position on this point very clearly: "It is well recognized that declarations made by way of unilateral acts, concerning legal or factual situations, may have the effect of creating legal obligations.  Declarations of this kind may be, and often are, very specific. When it is the intention of the State making the declaration that it should become bound according to its terms, that intention confers on the declaration the character of a legal undertaking, the State being thenceforth legally required to follow a course of conduct consistent with the declaration." (I.C.J. Reports 1974, p. 267, para. 43; p. 472, para. 46.)

60.  In fact, the declarations, even though they are unilateral acts, establish a series of bilateral engagements with other States accepting the same obligation of compulsory jurisdiction, in which the conditions, reservations and time-limit clauses are taken into consideration.  In the establishment of this network of engagements, which constitutes the Optional-Clause system, the principle of good faith plays an important role; the Court has emphasized the need in international relations for respect for good faith and confidence in particularly unambiguous terms, also in the Nuclear Tests cases: "One of the basic principles governing the creation and performance of legal obligations, whatever their source, is the principle of good faith.  Trust and confidence are inherent in international cooperation, in particular in an age when this cooperation in many fields is becoming increasingly essential.  Just as the very rule of pacta sunt servanda in the law of treaties is based on good faith, so also is the binding character of an international obligation assumed by unilateral declaration.  Thus interested States may take cognizance of unilateral declarations and place confidence in them, and are entitled to require that the obligation thus created be respected." (Ibid, p. 268, para. 46 ; p. 473, para. 49.)

61.  The most important question relating to the effect of the notification is whether the United States was free to disregard the clause of six months' notice which, freely and by its own choice, it had appended to its 1946 Declaration.  In so doing the United States entered into an obligation which is binding upon it vis-a-vis other States parties to the Optional-Clause system. Although the United States retained the right to modify the contents of the 1946 Declaration or to terminate it, a power which is inherent in any unilateral act of a State, it has, nevertheless assumed an inescapable obligation towards other States accepting the Optional Clause, by stating formally and solemnly that any such change should take effect only after six months have elapsed as from the date of notice.

62.  The United States has argued that the Nicaraguan 1929 Declaration, being of undefined duration, is liable to immediate termination, without previous notice, and that therefore Nicaragua has not accepted "the same obligation" as itself for the purposes of Article 36, paragraph 2, and consequently may not rely on the six months' notice proviso against the United States.  The Court does not however consider that this argument entitles the United States validly to act in non-application of the time-limit proviso included in the 1946 Declaration.  The notion of reciprocity is concerned with the scope and substance of the commitments entered into, including reservations, and not with the formal conditions of their creation, duration or extinction.  It appears clearly that reciprocity cannot be invoked in order to excuse departure from the terms of a State's own declaration, whatever its scope, limitations or conditions.  As the Court observed in the Interhandel case: "Reciprocity enables the State which has made the wider acceptance of the jurisdiction of the Court to rely upon the reservations to the acceptance laid down by the other party.  There the effect of reciprocity ends.  It cannot justify a State, in this instance, the United States, in relying upon a restriction which the other party, Switzerland, has not included in its own Declaration." (I.C.J. Reports 1959, p. 23.)
 
The maintenance in force of the United States Declaration for six months after notice of termination is a positive undertaking, flowing from the time-limit clause, but the Nicaraguan Declaration contains no express restriction at all. It is therefore clear that the United States is not in a position to invoke reciprocity as a basis for its action in making the 1984 notification which purported to modify the content of the 1946 Declaration. On the contrary it is Nicaragua that can invoke the six months' notice against the United States -- not of course on the basis of reciprocity, but because it is an undertaking which is an integral part of the instrument that contains it.

63.  Moreover, since the United States purported to aa on 6 April 1984 in such a way as to modify its 1946 Declaration with sufficiently immediate effect to bar an Application filed on 9 April 1984, it would be necessary, if reciprocity is to be relied on, for the Nicaraguan Declaration to be terminable with immediate effect.  But the right of immediate termination of declarations with indefinite duration is far from established.  It appears form the requirements of good faith that they should be treated, by analogy, according to the law of treaties, which requires a reasonable time for withdrawal from or termination of treaties that contain no provision regarding the duration of their validity.  Since Nicaragua has in fact not manifested any intention to withdraw its own declaration, the question of what reasonable period of notice would legally he required does not need to be further examined: it need only be observed that from 6 to 9 April would not amount to a "reasonable time".

64.  The Court would also recall that in previous cases in which it has had to examine the reciprocal effect of declarations made under the Optional Clause, it has determined whether or not the "same obligation" was in existence at the moment of seising of the Court, by comparing the effect of the provisions, in particular the reservations, of the two declarations at that moment.  The Court is not convinced that it would be appropriate, or possible, to try to determine whether a State against which proceedings had not yet been instituted could rely on a provision in another State's declaration to terminate or modify its obligations before the Court was seised. The United States argument attributes to the concept of reciprocity, as embodied in Article 36 of the Statute, especially in paragraphs 2 and 3, a meaning that goes beyond the way in which it has been interpreted by the Court, according to its consistent jurisprudence. That jurisprudence supports the view that a determination of the existence of the "same obligation" requires the presence of two parties to a case, and a defined issue between them, which conditions can only be satisfied when proceedings have been instituted.  In the case of Right of Passage over Indian Territory, the Court observed that "when a case is submitted to the Court, it is always possible to ascertain what are, at that moment, the reciprocal obligations of the Parties in accordance with their respective Declarations" (I.C.J. Reports 1957, p. 143). "It is not necessary that the same obligation' should be irrevocably defined at the time of the deposit of the Declaration of Acceptance for the entire period of its duration.  That expression means no more than that, as between States adhering to the Optional Clause, each and all of them are bound by such identical obligations as may exist at any time during which the Acceptance is mutually binding." (Ibid., p. 144.)
 
The coincidence or interrelation of those obligations thus remain in a state of flux until the moment of the filing of an application instituting proceedings. The Court has then to ascertain whether, at that moment, the two  States accepted "the same obligation" in relation to the subject-matter of the proceedings; the possibility that, prior to that moment, the one enjoyed a wider right to modify its obligation than did the other, is without incidence on the question.

65.  In sum, the six months' notice clause forms an important integral part of the United States Declaration and it is a condition that must be complied with in case of either termination or modification.  Consequently, the 1984 notification, in the present case, cannot override the obligation of the  United States to submit to the compulsory jurisdiction of the Court vis-a-vis Nicaragua, a State accepting the same obligation.

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66.  The conclusion just reached renders it unnecessary for the Court to pass upon a further reason advanced by Nicaragua for the ineffectiveness of the 1984 notification.  An acceptance of the compulsory jurisdiction of the Court, governed in many respects by the principles of treaty law, cannot, Nicaragua argues, be contracted or varied by a mere letter from the United States Secretary of State.  Drawing attention to the provisions of the Constitution of the United States as to the power of making treaties, Nicaragua contends that the 1984 notification is, as a matter of United States law, a nullity, and is equally invalid under the principles of the law, of treaties, because it was issued in manifest violation of an internal rule of law of fundamental importance (cf. Art. 46 of the Vienna Convention on the Law of Treaties). However, since the Court has found that, even assuming that the 1984 notification is otherwise valid and effective, its operation remains subject to the six months' notice stipulated in 1946, and hence it is inapplicable in this case, the question of the effect of internal constitutional procedures on the international validity of the notification does not have to be determined.

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67.  The question remains to be resolved whether the United States Declaration of 1946, though not suspended in its effects vis-a-vis Nicaragua by the 1984 notification, constitutes the necessary consent of the United States to the jurisdiction of the Court in the present case, taking into account the reservations which were attached to the declaration. Specifically, the United States has invoked proviso (c) to that declaration, which provides that the United States acceptance of the Court's compulsory jurisdiction shall not extend to "disputes arising under a multilateral treaty, unless (1) all parties to the treaty affected by the decision are also parties to the case before the Court, or (2) the United States of America specially agrees to jurisdiction".
 
This reservation will be referred to for convenience as the "multilateral treaty reservation".  Of the two remaining provisos to the declaration, it has not been suggested that proviso (a), referring to disputes the solution of which is entrusted to other tribunals, has any relevance to the present case. As for proviso (b), excluding jurisdiction over "disputes with regard to matters which are essentially within the domestic jurisdiction of the United States of America as determined by the United States of America", the United States has informed the Court that it has determined not to invoke this proviso, but "without prejudice to the rights of the United States under that proviso in relation to any subsequent pleadings, proceedings, or cases before this Court".

68.  The United States points out that Nicaragua relies in its Application on four multilateral treaties, namely the Charter of the United Nations, the Charter of the Organization of American States, the Montevideo Convention on Rights and Duties of States of 26 December 1933, and the Havana Convention on the Rights and Duties of States in the Event of Civil Strife of 20 February 1928.  In so far as the dispute brought before the Court is thus one "arising under' those multilateral treaties, since the United States has not specially  agreed to jurisdiction here, the Court may, it is claimed, exercise jurisdiction only if all treaty parties affected by a prospective decision of the Court are also parties to the case.  The United States explains the rationale of its multilateral treaty reservation as being that it protects the United States and third States from the inherently prejudicial effects of partial adjudication of complex multiparty disputes.  Emphasizing that the reservation speaks only of States "affected by" a decision, and not of States having a legal right or interest in the proceedings, the United States identifies, as States parties to the four multilateral treaties above mentioned which would be "affected", in a legal and practical sense, by adjudication of the claims submitted to the Court, Nicaragua's three Central American neighbours, Honduras, Costa Rica and El Salvador.

69.  The United States recognizes that the multilateral treaty reservation applies in terms only to "disputes arising under a multilateral treaty", and notes that Nicaragua in its Application asserts also that the United States has "violated fundamental rules of general and customary international law". However, it is nonetheless the submission of the United States that  all the claims set forth in Nicaragua's Application are outside the jurisdiction of the Court.  According to the argument of the United States, Nicaragua's claims styled as violations of gener