Executive agreements?that is, international agreements concluded between heads of state or their representatives, commonly without the necessity of parliamentary approval?are nowhere explicitly authorized in the Constitution. The Constitution is silent about international agreement-making except as it vests in the President, in cooperation with the Senate, the power to make and enter into treaties. Nevertheless the principle has long been established that the capacity of the United States to negotiate and enter into international agreements is not exhausted by the TREATY POWER. This principle has been repeatedly recognized in the actual conduct of United States FOREIGN AFFAIRS since the early days of the Republic. Since the mid-nineteenth century, but especially since WORLD WAR II, the use of executive agreements in United States practice has exceeded the use of treaties by an increasingly wide margin.
The expression "executive agreement," which is not widely used outside the United States but which has its equivalents abroad, is understood by the Department of State to refer, in general, to any international agreement brought into force relative to the United States without the ADVICE AND CONSENT of the Senate that is constitutionally
required for treaties. In particular, it is understood to refer to three kinds of agreements: those made pursuant to, or in accordance with, an existing treaty; those made subject to congressional approval or implementation ("congressional-executive agreements"); and those made under, and in accordance with, the President's constitutional powers ("sole executive agreements"). None of these executive agreements is subject to the formal treaty-making process specified in Article II, section 2, clause 2, of the Constitution.
A treaty-based executive agreement, provided that it is within the intent, scope, and subject matter of the parent treaty, has the same validity and effect as the treaty itself and is subject to the same constitutional limitations. Deriving from one of the elements of "the supreme law of the land," it takes precedence over all inconsistent state laws and follows the customary rule favoring the instrument later in time in case of inconsistency with a federal statute. A conspicuous example of a treaty-based executive agreement is the traditional compromis defining the terms of submission to adjudication or arbitration under a basic convention. Another is...