[857] See Grotius, III. c. 22.
Constitutional Restrictions.
§ 497. Although the heads of States are regularly, according to the Law of Nations, the organs that exercise the treaty-making power of the States, constitutional restrictions imposed upon the heads concerning the exercise of this power are nevertheless of importance for the Law of Nations. Such treaties concluded by heads of States or representatives authorised by these heads as violate constitutional restrictions are not real treaties and do not bind the State concerned, because the representatives have exceeded their powers in concluding the treaties.[858] Such constitutional restrictions, although they are not of great importance in Great Britain,[859] play a prominent part in the Constitutions of most countries. Thus, according to article 8 of the French Constitution, the President exercises the treaty-making power; but peace treaties and such other treaties as concern commerce, finance, and some other matters, are not valid without the co-operation of the French Parliament. Thus, further, according to articles 1, 4, and 11 of the Constitution of the German Empire, the Emperor exercises the treaty-making power; but such treaties as concern the frontier, commerce, and several other matters, are not valid without the co-operation of the Bundesrath and the Reichstag. Again, according to article 2, section 2, of the Constitution of the United States, the President can only ratify treaties with the consent of the Senate.
[858] The whole matter is discussed with great lucidity by Nippold, op. cit. pp. 127-164; see also Schoen, loc. cit.
[859] See Anson, "The Law and Custom of the Constitution," II. (2nd ed.), pp. 297-300.
Mutual Consent of the Contracting Parties.
§ 498. A treaty being a convention, mutual consent of the parties is necessary. Mere proposals made by one party and not accepted by the other are, therefore, not binding upon the proposer. Without force are also pollicitations which contain mere promises without acceptance by the party to whom they were made. Not binding are, lastly, so-called punctationes, mere negotiations on the items of a future treaty, without the parties entering into an obligation to conclude that treaty. But such punctationes must not be confounded either with a preliminary treaty or with a so-called pactum de contrahendo. A preliminary treaty requires the mutual consent of the parties with regard to certain important points, whereas other points have to be settled by the definitive treaty to be concluded later. Such preliminary treaty is a real treaty and therefore binding upon the parties. A pactum de contrahendo requires likewise the mutual consent of the parties. It is an agreement upon certain points to be incorporated in a future treaty, and is binding upon the parties. The difference between punctationes and a pactum de contrahendo is, that the latter stipulates an obligation of the parties to settle the respective points by a treaty, whereas the former does not.
Freedom of Action of consenting Representatives.
§ 499. As a treaty will lack binding force without real consent, absolute freedom of action on the part of the contracting parties is required. It must, however, be understood that circumstances of urgent distress, such as either defeat in war or the menace of a strong State to a weak State, are, according to the rules of International Law, not regarded as excluding the freedom of action of a party consenting to the terms of a treaty. The phrase "freedom of action" applies only to the representatives of the contracting States. It is their freedom of action in consenting to a treaty which must not have been interfered with and which must not have been excluded by other causes. A treaty concluded through intimidation exercised against the representatives of either party or concluded by intoxicated or insane representatives is not binding upon the party so represented. But a State which was forced by circumstances to conclude a treaty containing humiliating terms has no right afterwards to shake off the obligations of such treaty on the ground that its freedom of action was interfered with at the time.[860] This must be emphasised, because in practice such cases of repudiation have frequently occurred. A State may, of course, hold itself justified by political necessity in shaking off such obligations, but this does not alter the fact that such action is a breach of law.
[860] See examples in Moore, V. § 742.