The framers required a Senate supermajority for treaties to ensure broad national support for binding commitments abroad. Over time, Presidents and Congress developed other ways to make international deals, and today most agreements never go to the Senate as treaties. The choice of form affects how durable a commitment is and how easily a later President can undo it.
This guide explains the types of international agreements, how they are approved and ended, and the debates over their use.
Most international agreements are executive agreements. Congressional-executive agreements are authorized or approved by ordinary majorities in both houses, often under trade promotion authority, and include NAFTA, the World Trade Organization agreements, and the U.S.-Mexico-Canada Agreement. Sole executive agreements rest on the President's own constitutional powers, such as the 2015 Iran nuclear deal and the Paris climate agreement. The Case-Zablocki Act of 1972 requires the State Department to report executive agreements to Congress.
The Constitution is silent on how to end treaties. In Goldwater v. Carter in 1979, the Supreme Court dismissed a challenge to President Carter's termination of a defense treaty with Taiwan, and Presidents have since withdrawn from treaties on their own, including the Anti-Ballistic Missile Treaty in 2002 and the Intermediate-Range Nuclear Forces Treaty in 2019. In 2023 Congress passed a law barring the President from withdrawing from NATO without Senate consent or an act of Congress. Sole executive agreements are especially easy for later Presidents to undo.
The United States left the Paris Agreement in 2020, rejoined in 2021, and announced withdrawal again in January 2025. In 2025 it also announced withdrawal from the World Health Organization, the UN Human Rights Council, and UNESCO, and the administration reviewed participation in other international organizations. The WHO withdrawal took effect on January 22, 2026, and a memorandum that month ordered withdrawal from 66 more international organizations and bodies, 31 of them affiliated with the UN, including the UN climate change convention and the Intergovernmental Panel on Climate Change. Supporters said these organizations were ineffective or contrary to American interests, while critics said the withdrawals reduced American influence and reliability as a partner.
Supporters of executive agreements say they are flexible and necessary in a world of thousands of international commitments, and that the treaty process has become nearly impossible amid partisan divisions. Critics say Presidents use executive agreements to bypass the Senate on major commitments and that such deals lack durability and democratic legitimacy. Many scholars also debate whether Presidents should be able to withdraw from Senate-approved treaties without congressional approval, and some propose requiring congressional consent for withdrawals from major agreements.
The Supremacy Clause makes treaties part of the supreme law of the land, binding on the states. In Missouri v. Holland in 1920, the Court upheld a migratory bird treaty that Congress could not otherwise have imposed on the states. But in Medellin v. Texas in 2008, it held that a treaty is not enforceable in U.S. courts unless it is self-executing or Congress passes implementing legislation. When a later statute conflicts with an earlier treaty, the later in time generally controls domestically, even if the United States remains bound internationally.
The President, usually through the State Department, negotiates and signs treaties, then submits them to the Senate. The Foreign Relations Committee holds hearings and reports a resolution of ratification, often with reservations, understandings, or declarations that limit or interpret U.S. obligations. If two-thirds of senators present agree, the President may ratify the treaty. The Senate has approved more than 1,500 treaties and rejected about two dozen, most famously the Treaty of Versailles in 1919 and 1920 and the Comprehensive Nuclear-Test-Ban Treaty in 1999. Many others have been left pending for years.
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