2) A treaty, to be valid, must be the expression of an agree ment. Unlike a private contract, however, it is not voidable on proof that one of the parties to it was subject to duress, but only if it can be proved that the individual negotiator has been so subject. Thus a treaty imposed by the victor upon the van quished remains valid, though signed under pressure of force.
3) In modern practice a treaty, though executed by agents with full powers, is not valid until it has been ratified. Ratifica tion, though formerly not thought to be necessary for "declara tions," such as the Declaration of Paris in 1856, was expressly stipulated in those of the conferences of 1899 and 1907.
4) The question of the language employed in treaties at one time caused trouble. In the 16th century all international treaties were drawn 'up in Latin, more rarely in French, and it was not till the 18th century that the latter was generally accepted (except by the pope and the emperor) as the language of diplomacy (the Anglo-French commercial treaty of April II, 1713 was in Latin). The present practice is that, when treaties or conventions are concluded between more than two Powers they are drawn up in French, but when between two Powers only, there are usually two texts, one in each language, both of which are signed by the plenipotentiaries of the two parties. Such bi-lingual treaties are sometimes accompanied by a third version in French, to be de cisive in case of a difference of opinion as to the precise meaning of the language of the other texts.
5) The making of a treaty is sometimes accompanied by acts intended to secure its due performance, e.g., the occupation of the German Rhine Provinces by the Allied Powers pending the pay ment of the reparations imposed by the Treaty of Versailles.
6) Art. XVIII. of the Covenant of the League of Nations lays down that every treaty or international agreement entered into after the signature and ratification of the Treaty of. Ver sailles by any member of the League shall be forthwith registered with the Secretariat and shall as soon as possible be published by it; and that no such treaty or international agreement shall be binding until so registered.
Duration of Treaties.—The question of when, and in what circumstances, the obligations incurred under treaties, nominally perpetual, come to an end has been the subject of much debate. A treaty may lapse naturally by the destruction of one of the States party to it, or by the object of the agreement ceasing to ,exist; or it may be denounced by one of the parties under powers reserved in the treaty itself. Treaties are also in most cases sus pended, if not terminated, by war between the contracting parties, and are therefore usually revived in express terms in the treaty of peace. More debatable is the proposition upheld by certain jurists, e.g., Bynkershoek, that the condition rebus sic stantibus is implicit in every treaty. This is laid down by Bismarck, in his Reminiscences, as self-evident, and he adds that "treaties are only valid so long as they are reinforced by the interests of the parties to them." In practice this was certainly often the case and—as is pointed out in the latter part of this article—no alteration was made in this respect by the London Protocol of 1871, which laid down the principle that "no Power can liberate itself from the engagements of a treaty, nor modify the stipulations thereof, unless with the consent of the contracting Powers, by means of an amicable agreement." Art. XIX. of the Covenant is an at tempt to meet the difficulty. It lays down that "the Assembly may from time to time advise the reconsideration by members of the League of treaties which have become inapplicable." This provision, though it suggests no more than advice backed by com bined moral pressure, may be open to the objection that it tends to keep alive the agitation among the peoples discontented with the settlements made under certain treaties, by suggesting that these are not to be considered as final. On the other hand, it may be argued that it provides a safety-valve for discontent by holding out the hope of a revision otherwise than by war.
The Inviolability of Treaties.—Since the whole structure of international relations, as regulated by law, is based upon treaties, it follows that anything that tends to weaken men's faith in, and respect for treaties must loosen this structure. For this reason it is all-important that treaties, once made, should be kept in the letter and in the spirit ; and this again involves the principle that nothing should be included in a treaty which the parties to it are not reasonably sure that they and their successors will be able to carry out in any circumstances. This was a principle firmly maintained by British statesmen during the 19th century, from Pitt and Castlereagh onwards, and led them to avoid commit ments "for eventual exertion" in circumstances which could not be foreseen. For the same reason, in the days of the old diplomacy, there was in the language of treaties of peace, and of diplomatic intercourse generally, a studied avoidance of anything that might keep open old sores by any unnecessary wounding of the feelings of the vanquished. Thus, while the preambles to treaties of
peace were perhaps apt to lay overmuch stress on the complete cordiality of the restored relations, and so be open to the charge of being "false-friendly," they at least made it clear that the articles of the treaty which followed were the conditions on which old scores would be completely wiped out. In this respect the Treaty of Versailles of 1919, e.g., compares unfavourably with the Treaty of Versailles of 1783. In the former the defeated nation was compelled to confess its "war-guilt," whether it be lieved itself guilty or not, and the terms of the penance which was to be the price of its restoration to the communion of na tions were built into the very foundations of the new international organization. This has rankled in the minds of the Germans, and so has neither made for peace nor for that respect for treaty obligations on which peace is based. The framers of the treaty of 1783 were wiser. Art. I. of the treaty ends with the words : "There shall be complete oblivion of and amnesty for all that may have been done or committed before or during the war which has now come to an end." Many treaties containing what were technically known as "transitory conventions" with reference to recognition, bound aries or cessions of territory have become, as it were, the title deeds of the nations to which they relate. This may be said to date from the treaties of Osnabriick and Miinster (Westphalia) in 1648, which were the work of the first international congress, and were recognized as giving a new juridical basis to the terri torial system of Europe. Although, in the i8th century, treaties were more honoured in the breach than the observance, it was considered expedient to veil even the most flagrant acts of ag gression under legal forms, as in the case of the three partitions of Poland which, as Gentz observed, set an unhappy precedent, for the aggressions of Revolutionary France. The treaties con cluded between the Powers after the downfall of Napoleon (I. Paris, 1814, Vienna Final Act, 1815, II. Paris, 1815, and Frank furt, 1819), represented an attempt to reorganize the European territorial system on a sound basis, by endowing the reconstituted States with unimpeachable title-deeds and ensuring their stability by establishing a balance of power between them. Other treaties —the treaty of Chaumont in March 1814, and the treaty of al liance of Nov. 20, 1815 which was based upon it—provided for the continuance of the Quadruple Alliance for the purpose of watching over and safeguarding the settlement thus made. And, though this "federal system" for Europe broke down for various reasons (see EUROPE), the idea of "the treaties" as the founda tion of the European system, and of the "Concert of Europe" as their guardian, survived long enough to secure an unprecedented period of peace. The principle that the treaties could not be altered without the consent of "Europe" was also more or less effectively asserted: effectively in the case of the treaties of 1831 and 1839 which separated Belgium from the Netherlands, in effectively in the protests of France and Great Britain against Russia's violation of the terms of the Treaty of Vienna by her treatment of the Poles in 1830 and 1863.
The principle of the solidarity of Europe in the matter of ter ritorial changes was even extended to the questions arising out of the disintegration of the Ottoman empire, which had been ex cluded from the treaties of 1815; and the Concert of Europe survived in the Eastern Question (q.v.) long after the results of the Italian war of 1859 and of the wars of 1864, 1866 and 187o-71 had blown the Vienna settlement to pieces. Thus the partition of Turkey was regulated by the great Powers, or some of them, in the treaties of London, 1832, 1863, 1864, and of Constantinople, 1881, with reference to Greece; and by the treaties of Paris 1856, London 1871, Berlin 1878, London 1885, with reference to Montenegro, Rumania, Serbia, Bulgaria and the navigation of the Danube. As the result of the World 'War, these settlements have undergone very extensive and important changes; but they still have an effective existence, as the ultimate title-deeds of the Balkan States.
In general, the history of treaties and treaty-making during the century that followed the Congress of Vienna showed a notable advance in the sense of international obligation as compared with the standpoint of the i8th century. That the system evolved was very far from satisfactory was proved all too clearly by the World War. The League of Nations, although based on the some what unstable foundations of the Treaty of Versailles, is a bold attempt to substitute for 19th century methods a system better calculated to preserve peace. (W. A. P.)