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, al1 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 10 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 finaljudgment in the case, it would keep the matters covered by the Order continuously under review.
. . .
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. . . .
On behalf of Nicaragua,
at the end of the Memorial
"Nicaragua subrnits 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."
"May it please the Court, on behalf of the United States of America, to adjudge and declare, for each and al1 of the foregoing reasons, that the claims set forth in Nicaragua's Application of 9 April1984 (1) are not within the jurisdiction of this Court and (2) are inadmissible."
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1 1. 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 para- military 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 Appli- cation by which it was brought before the Court. The issue being thus limited, the Court will avoid not only al1 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 al1 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, whch 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 1 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 proposa1 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 officia1 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 :
(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 dispatched to Geneva. . . .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 the basis of these facts, the United States contends, first, that Nicaragua never became a party to the Statute of the Permanent Court 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 durée qui n'est pas encore expirée", 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 durée qui n'est pas encore expirée" 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 borne 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.
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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 corning 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, 1. 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 not 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-à-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 potential 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.
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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 officia1 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 tanta- mount 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 reproduc- tion 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 jurisdic- tion 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 para- graph 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 forma1 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.
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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 the 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-à-vis Nicaragua, even if not effective erga omnes. As already explained, one contention of the United States in relation toits 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). . . .
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61. The most important question relating to the effect of the 1984 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-à-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 forma1 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 whch 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 Declara- tion. 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 act 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 from 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 be 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".
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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.