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.