§ 534. The binding force of treaties may terminate in four different ways, because a treaty may either expire, or be dissolved, or become void, or be cancelled.[901] The grounds of expiration of treaties are, first, expiration of the time for which a treaty was concluded, and, secondly, occurrence of a resolutive condition. Of grounds of dissolution of treaties there are three—namely, mutual consent, withdrawal by notice, and vital change of circumstances. In contradistinction to expiration and dissolution as well as to voidance and cancellation, performance of treaties does not terminate their binding force. A treaty whose obligation has been performed is as valid as before, although it is now of historical interest only.
[901] The distinction made in the text between fulfilment, expiration, dissolution, voidance, and cancellation of treaties is, as far as I know, nowhere sharply drawn, although it would seem to be of considerable importance. Voidance and cancellation will be discussed below, §§ [540]-544 and [545]-549.
Expiration through Expiration of Time.
§ 535. All such treaties as are concluded for a certain period of time only, expire with the expiration of such time, unless they are renewed or prolonged for another period. Such time-expiring treaties are frequently concluded, and no notice is necessary for their expirations, except when specially stipulated.
A treaty, however, may be concluded for a certain period of time only, but with the additional stipulation that the treaty shall after the lapse of such period be valid for another such period, unless one of the contracting parties gives notice in due time.
Expiration through Resolutive Condition.
§ 536. Different from time-expiring treaties are such as are concluded under a resolutive condition, which means under the condition that they shall at once expire with the occurrence of certain circumstances. As soon as these circumstances arise, the treaties expire.
Mutual Consent.
§ 537. A treaty, although concluded for ever or for a period of time which has not yet expired, may nevertheless always be dissolved by mutual consent of the contracting parties. Such mutual consent can become apparent in three different ways.
First, the parties can expressly and purposely declare that a treaty shall be dissolved; this is rescission. Or, secondly, they can conclude a new treaty concerning the same objects as those of a former treaty without any reference to the latter, although the two treaties are inconsistent with each other. This is substitution, and in such a case it is obvious that the treaty previously concluded was dissolved by tacit mutual consent. Or, thirdly, if the treaty is such as imposes obligations upon one of the contracting parties only, the other party can renounce its rights. Dissolution by renunciation is a case of dissolution by mutual consent, since acceptance of the renunciation is necessary.