(g) A treaty is voidable when, (1) it is concluded in excess of powers of contracting parties, (2) when it is concluded because of stress of force upon negotiators or because of fraud, (3) when the conditions threaten the self-preservation of the state or its necessary attributes. Hall gives as the test of voidability the following: "Neither party to a contract can make its binding effect dependent at his will upon conditions other than those contemplated at the moment when the contract was entered into, and on the other hand a contract ceases to be binding so soon as anything which formed an implied condition of its obligatory force at the time of its conclusion is essentially altered."[281] The condition rebus sic stantibus is always implied.

(h) A treaty may be terminated by the simple act of denunciation when this right of denunciation is specified in the treaty itself, or when the treaty is of such a nature as to be voidable by an act of one of the parties.

[CHAPTER XV]

AMICABLE SETTLEMENT OF DISPUTES AND NON-HOSTILE REDRESS

[§ 88. The Amicable Settlement of Disputes]

It is now generally admitted that in the settlement of international disputes war should be regarded as a last resort. Other means of amicable settlement should be exhausted before any measures of force are tried. Among these amicable means the most common are diplomatic negotiations, the good offices or friendly mediation of a third state, conferences and congresses, and arbitration.[282]

(a) The settlement of disputes by diplomatic negotiation follows the ordinary course of diplomatic business, whether committed to the regular or to special agents. The larger number of disputed questions are settled by diplomatic negotiation.

(b) In the case of disputes which are not easily settled by diplomatic negotiations, a third state, friendly to the disputants, sometimes offers its good offices as mediator to bring about an agreement. The office of the mediating state is not to judge upon the merits of the disputed question, but to devise a practicable means of settlement of the question in view of the circumstances of the dispute. The tender of good offices is a measure involving the least possible interference in the dispute, and cannot be regarded as other than a friendly act. There is no obligation to accept the tender, and either disputant may decline it without offense. One of the disputants may request the tender of good offices or of mediation. The distinction between good offices and mediation is not always made in practice, though it may be said that good offices extend only to the establishing of bases of negotiations and the commencement of the negotiations. The more direct work of carrying on the negotiations is of the nature of mediation. Either party may at the beginning or at any time refuse the mediator's offices.