CONGRESS, in diplomacy, a solemn assembly of sovereigns or their plenipotentiaries met together for the purpose of definitely settling international questions of common interest. In this sense the word first came into use in the 17th century; an isolated in stance occurs in 1636, when it was applied to the meeting of dele gates summoned by the pope to Cologne, to attempt to put an end to the Thirty Years' War. In 1647 the meetings of delegates for the conclusion of peace, assembled at Osnabruck and Munster, were termed a congress ; and in spite of objections to it on the ground that it was "coarse and inappropriate," based on the physiological sense of the word (Lat. congressus), it continued thenceforward in use.
The adoption of the name Congress for the national legislative body in the United States (and so for other American countries) was simply a development from this usage ; for the "continental congresses" of 1774 and 17 7 and the "congress of the con federation" (1781-88) were, as inter-state representative delibera tive bodies, analogous to international congresses, and the Con gress established under the Federal Constitution of 1789 ulti mately consists of representatives of the sovereign States com posing the Union (see UNITED STATES : Constitution and Gov ernment). The more general analogous use of the term (Church Congress, etc.) is of modern origin.
In its international sense the term "congress" has usually only been applied to gatherings of first-class importance, attended either by the sovereigns themselves or by their secretaries of State for foreign affairs, less important meetings being termed "confer ences." The dividing-line between the congress and conference is, however, historically ill-defined, the two terms having often been used indifferently in official diplomatic correspondence even of such dignified assemblages as the meetings of sovereigns and statesmen at Aix-la-Chapelle (1818) , Troppau (18 2o) and Lai bach (1821). Since the World War, indeed, the word "congress" has fallen into disuse, even the great assemblage of its representa tives of the Allied and Associated Powers which settled the terms of the Treaty of Versailles being known as the Conference of Paris.
The results of the work done at various international con gresses and conferences in developing a sense of the common interests of nations are dealt with under INTERNATIONAL LAW and allied articles; while the more important congresses are treated under their topographical headings.
Convocation and Constituent Elements of a Congress.— Any sovereign Power has the right to issue invitations to a con gress or conference. In principle, moreover, every State directly concerned in the matters to be discussed has the right to be repre sented. But this principle, though affirmed by the Powers at Aix la-Chapelle in 1818, has rarely been translated into practice. At the congress of Vienna 0814-15), the decisions of which affected every State in Europe, a committee of the five great Powers claimed and exercised the right to settle everything of importance; and this set the precedent which has been followed ever since. At the congresses of Paris (1856) and Berlin (1878), as at that of Vienna, the great Powers regulated the affairs of lesser States without consulting the representatives of the latter. Similarly, at the conference of 1869 on the affairs of Crete no representative of Greece was present ; and at the conference of London (1883), on the international regulation of the Danube, the sovereign state of Rumania, though a Danubian power, was not represented.
This procedure naturally caused much dissatisfaction among the lesser Powers, and led to frequent protests on their part from the Congress of Vienna onward. But, although the principle of the equality of all sovereign States was admitted in theory, such at tempts as were made to apply it in practice, e.g., at the Hague Conferences, proved most unsatisfactory. At the Peace Confer ence of Paris, though lip-service was paid to the rights of small nationalities, all matters of importance were settled by the Big Four in secret conference, the full public sessions being mere dress parades. Under the Covenant of the League of Nations, however, an attempt was made to secure the rights of small States, and so far as the right to be heard is concerned, this was done; but effective decisions can only be made by the Council, in which the great Powers preponderate, or with its consent. The Council and Assembly together form, in effect, a permanent congress, though the name is not applied to the Geneva meetings. The practical in convenience of the theoretical equality of all sovereign states, and of the necessity for unanimity in all decisions, was well illustrated when the protracted efforts of the Assembly to "interpret" the obnoxious article X of the Covenant were defeated by the iso lated vote of Persia.
Procedure.—When the congress assembles the first business is the verification of powers, which is done by a commission spe cially appointed to examine the credentials of the plenipoten tiaries. If the foreign minister himself attend, he needs no creden tials; those of his colleagues are countersigned by him. The veri fication being completed, questions of procedure, of precedence and the like, are settled. The question of precedence which, in earlier times caused much trouble, was settled by the rule observed at the congress of Berlin (1878), according to which the pleni potentiaries took their seat at a horse-shoe table in the alphabeti cal order of the states they represented, according to the French alphabet.
The presidency of the congress is by courtesy reserved for the minister for foreign affairs of the state in which the meeting is held ; if, however, he decline to serve, a president is elected; or, if there be a mediating Power, the minister representing this presides.
The discussions are governed by carefully defined rules. Thus every proposition must be presented in writing, and all decisions to be binding on all must be unanimous. The secretary keeps the minutes of each session, which are signed by all present and read at the next meeting. This protoco/—as it has been called since the congress of Vienna—takes the form of a bald, but very exact resume of important points discussed, ending with a record of the conclusions and resolutions arrived at. If there be no such results, opinions are recorded. If any plenipo tentiary dissent from the general opinion, such dissent must be recorded in the protocol. Sometimes short signed memoranda, known as a vote or opinion, are attached to the protocol, stating the reasons that have governed the Powers in question in agreeing to a given conclusion. Individual Powers may express their dis sent in two ways: either by placing such dissent on record, or by withdrawing altogether from the sessions of the congress. The conclusions arrived at after the discussion of the various subjects before the congress are usually embodied in separate conventions, duly signed by the Powers who are a party to them. Finally, these separate conventions are brought together in an inclusive treaty, signed by all the plenipotentiaries present, known as the Final Act.