Treaty Law and Legal Definition

A treaty is a binding agreement under international law, entered by parties who are subject to international law, mainly states and international organizations. It is a pact formed between two nations or communities, each with the right of self-government. It is not essential that each party posses the same rights to give force to the treaty, simply that each party have the recognized right of self-government, and the power to perform the terms of the treaty. Article II, Section 2 of the United States Constitution grants power to the President to make treaties with the "advice and consent" of two thirds of the Senate.

A multilateral treaty has several parties, and establishes rights and obligations between each party and every other party. Multilateral treaties are usually open to any state; others are regional. Bilateral treaties by contrast are negotiated between a limited number of states, most commonly only two, establishing legal rights and obligations between those two states only. However, a bilateral treaty may have more than two parties.