A compact made between two or more independent nations with a view to the public WELFARE.
A treaty is an agreement in written form between nation-states (or international agencies, such as the UNITED NATIONS, that have been given treaty-making capacity by the states that created them) that is intended to establish a relationship governed by INTERNATIONAL LAW. It may be contained in a single instrument or in two or more related instruments such as an exchange of diplomatic notes. Various terms have been used for such an agreement, including treaty, convention, protocol, declaration, charter, COVENANT, pact, act, statute, exchange of notes, agreement, modus vivendi ("manner of living" or practical compromise), and understanding. The particular designation does not affect the agreement's legal character.
Though a treaty may take many forms, an international agreement customarily includes four or five basic elements. The first is the preamble, which gives the names of the parties, a statement of the general aims of the treaty, and a statement naming the plenipotentiaries (the persons invested with the power to negotiate) who negotiated the agreement and verifying that they have the power to make the treaty. The substance of the treaty is contained in articles that describe what the parties have agreed upon; these articles are followed by an article providing for ratification and the time and place for the exchange of ratifications. At the end of the document is a clause that states "in witness whereof the respective plenipotentiaries have affixed their names and seals" and a place for signatures and dates. Sometimes additional articles are appended to the treaty and signed by the plenipotentiaries along with a declaration stating that the articles have the same force as those contained in the body of the agreement.
Article II, Section 2, Clause 2, of the U.S. Constitution gives the president the power to negotiate and ratify treaties, but he must obtain the advice and consent of the Senate (in practice solicited only after negotiation); two-thirds of the senators present must concur. Article I, Section 10, of the Constitution forbids the states to enter into a "treaty, alliance, or confederation," although they may enter into an "agreement or compact" with other states, domestic or foreign, but only with the consent of Congress.
The U.S. Supreme Court, in Missouri v. Holland, 252 U.S. 416, 40 S. Ct. 382, 64 L. Ed. 641 (1920), established that U.S. treaties are superior to state law. Acts of Congress, however, are equivalent to a treaty. Thus, if a treaty and a law of Congress are inconsistent, the one later in time prevails. The Court has never found a treaty to be unconstitutional, and few treaties have been challenged. In general, the Court views a dispute over a treaty as a POLITICAL QUESTION outside its jurisdiction.
Traditionally, international law required treaties to be ratified in the same form by all parties. Consequently, reservations or amendments proposed by one party had to be accepted by all. Because of the large number of participating states, this unanimity rule has proved difficult to enforce in modern multilateral treaties sponsored by international agencies for the purpose of creating legal regimes or codifying rules of international law. Where agreement exists on the essential elements of a treaty, international law increasingly is allowing reservations as to minor points not unanimously accepted. Treaties for which ratification is specified come into effect upon the exchange of ratifications between the parties or upon deposit of the ratifications with a designated party or international agency, such as the Secretariat of the United Nations.
A treaty may be terminated in accordance with specifications in the treaty or by consent of the parties. War between the parties does not invariably terminate treaties, as some treaties are made to regulate the conduct of hostilities and treatment of prisoners. Other treaties may be suspended for the duration of the hostilities and then resumed. An unjustified, unilateral abrogation of a treaty may give rise to possible international claims for any injury suffered by the other parties.
Treaties are usually interpreted according to the ordinary sense of their words in context and the apparent purposes to be achieved. If the meaning of the language is unclear or there is doubt that it expresses the intention of the parties, the work product of the negotiation process may be consulted as well as other extrinsic evidence.