Treaties and International Agreements: How the U.S. Makes Them

Reference · Understanding American Government

In brief: Under the Constitution, the president negotiates treaties, but a treaty binds the United States only after two-thirds of the senators present vote to approve it. Most U.S. international agreements, however, are not treaties in this constitutional sense: they are executive agreements, congressional-executive agreements approved by both houses, or nonbinding political commitments. Presidents have also ended treaties on their own authority, a practice the Supreme Court has never squarely ruled on.

What is a treaty under the U.S. Constitution?

Article II, Section 2 gives the president power “by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur.” The vote is two-thirds of senators present and voting, not two-thirds of the full Senate.

Once in force, a treaty is binding under international law. Under the Supremacy Clause, it is also part of “the supreme Law of the Land,” with the force of federal law, according to the U.S. Senate’s overview of its treaty powers. Some treaties take effect in U.S. courts directly (“self-executing”); others need Congress to pass implementing legislation first.

How is a treaty ratified?

A common misconception is that the Senate “ratifies” treaties. In fact, the Senate gives (or withholds) its consent, and the president ratifies. The process usually runs like this:

• The executive branch negotiates the text and the president (or a delegate) signs it.
• The president sends the treaty to the Senate, where it goes first to the Committee on Foreign Relations.
• The committee reports a resolution of ratification, which may include reservations, understandings or declarations.
• The full Senate votes; approval requires two-thirds of senators present.
• The president completes ratification by exchanging or depositing the instruments of ratification with the other country or countries.

The Senate has approved the great majority of treaties sent to it. When leaders expect a treaty to fail, they often simply never schedule a vote, and treaties can sit before the Foreign Relations Committee for years.

What are the different kinds of international agreements?

The Congressional Research Service (CRS report RL32528) notes that commentators estimate more than 90% of U.S. international agreements are executive agreements rather than Article II treaties. The main categories are:

• Treaties (Article II): approved by two-thirds of the Senate. Examples: the NATO treaty and the Chemical Weapons Convention.
• Congressional-executive agreements: approved by a simple majority of both the House and the Senate, like an ordinary law. Major trade deals use this route. NAFTA was approved this way, and so was its successor, the U.S.-Mexico-Canada Agreement (USMCA): the House passed the implementing bill 385-41 on December 19, 2019, the Senate passed it 89-10 on January 16, 2020, and it entered into force on July 1, 2020 (CRS report R44981).
• Executive agreements pursuant to a treaty: made under authority Congress or the Senate already granted in an earlier treaty.
• Sole executive agreements: made on the president’s own constitutional authority, without a vote of Congress.
• Nonbinding political commitments: arrangements that carry political and moral weight but create no legal obligation.

The Iran nuclear deal (the Joint Comprehensive Plan of Action, or JCPOA, 2015) is the best-known recent political commitment. In a 2015 letter to Congress, the State Department said the JCPOA “is not a treaty or an executive agreement, and is not a signed document,” but a set of political commitments (Lawfare). The United States left the JCPOA in 2018.

The Paris Agreement on climate change (2015) is a mixed case. It is an international agreement, but the United States joined it by executive action without a Senate vote, and each country’s emissions target is set nationally rather than imposed as a legal obligation. That structure is why each president could join or leave without Congress.

How does the United States withdraw from a treaty?

The Constitution spells out how to make a treaty but says nothing about how to end one. In practice, presidents have withdrawn from treaties on their own, usually by giving the notice the treaty itself requires.

The key court case is Goldwater v. Carter (1979). President Jimmy Carter ended the 1954 Mutual Defense Treaty with Taiwan when the United States recognized the government in Beijing, and Senator Barry Goldwater and other lawmakers sued. On December 13, 1979, the Supreme Court ordered the case dismissed without deciding who holds the power (Cornell Legal Information Institute). Four justices called it a “political question” for the elected branches; Justice Lewis Powell said it was not ripe because Congress had not formally acted.

Notable withdrawals include:

• ABM Treaty: President George W. Bush gave notice on December 13, 2001, and the withdrawal took effect six months later, on June 13, 2002. A federal court dismissed a lawsuit by 32 House members challenging it (CRS report RS21088).
• INF Treaty: The United States suspended its obligations in February 2019, citing Russian violations, and withdrew on August 2, 2019 (CSIS Missile Threat).
• Paris Agreement (first time): President Trump announced withdrawal on June 1, 2017; formal notice followed on November 4, 2019, and took effect on November 4, 2020. President Biden rejoined, effective February 19, 2021.
• Paris Agreement (second time): President Trump announced a second withdrawal on January 20, 2025. It took effect on January 27, 2026, after the one-year waiting period (Harvard Environmental and Energy Law Program). On January 7, 2026, the administration also announced withdrawal from the UN Framework Convention on Climate Change, the underlying 1992 climate treaty.
• World Health Organization: Executive Order 14155, signed January 20, 2025, began the withdrawal, which took effect on January 22, 2026, after a one-year notice period (HHS fact sheet).

Congress has pushed back in at least one case. A 2023 law, codified at 22 U.S.C. § 1928f, bars the president from leaving the North Atlantic Treaty without Senate approval or an act of Congress (Brookings). No court has yet tested it.

For how presidents use unilateral tools more broadly, see our guide to executive orders.

What famous treaties has the Senate rejected?

The best-known failure is the Treaty of Versailles, which ended World War I and created the League of Nations. President Woodrow Wilson left senators off the U.S. negotiating team, and Senate Majority Leader Henry Cabot Lodge, chairman of the Foreign Relations Committee, insisted on reservations limiting U.S. obligations to the League. On November 19, 1919, the Senate rejected the treaty, the first time it had ever rejected a peace treaty (U.S. Senate Historical Office). A second vote in March 1920 also fell short of two-thirds, and the United States never joined the League.

Other treaties failed without a final vote. President Carter signed SALT II with the Soviet Union in 1979 but asked the Senate on January 3, 1980, to set it aside after the Soviet invasion of Afghanistan (Office of the Historian).

Which treaties and agreements shaped U.S. history?

The Senate approved the Chemical Weapons Convention 74-26 on April 24, 1997, days before it entered into force (Arms Control Association).

New START expired on February 5, 2026, leaving no legally binding limits on U.S. and Russian strategic nuclear forces for the first time in decades. Russia had suspended its participation in 2023. In September 2025, Russian President Vladimir Putin proposed that both sides informally observe the treaty’s limits for a year. The United States did not formally accept, and President Trump said it would seek a “new, improved, and modernized” treaty (Arms Control Association). As of October 2026, no successor treaty has been reported.

USMCA remains in force, but at its first six-year joint review on July 1, 2026, the United States declined to extend it. That triggers annual reviews, and the agreement runs until 2036 unless the parties extend it (IISD).

For major domestic laws, see landmark legislation. For the presidents who signed these agreements, see our history of American presidents.

Why do nations keep (or break) their agreements?

International agreements have no global police force behind them, so trust and expectations do much of the work. Researchers in political science and political psychology point to three forces.

• Reciprocity: In Robert Axelrod’s computer tournaments, described in The Evolution of Cooperation (1984), the strategy “tit for tat” (cooperate first, then copy the other side’s last move) consistently scored near the top. Cooperation was most stable when players expected to meet again, which Axelrod called “the shadow of the future” (summary).
• Reputation: Michael Tomz’s Reputation and International Cooperation (2007) studied three centuries of government borrowing. He found that a country’s track record, more than threats of punishment, shaped whether lenders trusted it (Princeton University Press).
• Commitment and perception: Not all scholars agree on how lasting reputations are. Jonathan Mercer’s Reputation and International Politics (1996) used a psychological approach to argue that a nation’s reputation is less durable, and less worth fighting for, than leaders often assume.

These ideas help explain why treaty withdrawals stir strong reactions: supporters often see protection of national interests, critics a cost to future trust. For ongoing commentary, see our politics section.

Key takeaways

• A treaty under Article II needs the approval of two-thirds of senators present; the president then ratifies it.
• Most U.S. international agreements are executive or congressional-executive agreements, not Article II treaties; some, like the JCPOA, are nonbinding political commitments.
• Presidents have withdrawn from treaties on their own, and in Goldwater v. Carter (1979) the Supreme Court declined to settle whether they may.
• Recent withdrawals include the ABM Treaty (2002), INF (2019), the Paris Agreement (2020 and again in 2026) and the WHO (2026); New START expired in February 2026.
• The Treaty of Versailles (1919–1920) remains the most famous Senate rejection of a treaty.

More in Understanding American Government

• The American Presidents: A Short History of the Office
• Executive Orders Explained: What They Are and How They Work
• Presidential Approval Ratings Through History
• Landmark Laws That Shaped America

Sources

• About Treaties — U.S. Senate
• The Senate Rejects the Treaty of Versailles — U.S. Senate
• International Law and Agreements: Their Effect upon U.S. Law (RL32528) — Congressional Research Service
• Goldwater v. Carter, 444 U.S. 996 (1979) — Cornell Legal Information Institute
• Withdrawal from the ABM Treaty: Legal Considerations — Congressional Research Service
• Paris Climate Agreement tracker — Harvard Environmental and Energy Law Program
• Fact Sheet: U.S. Withdrawal from the World Health Organization — HHS
• New START Expires As U.S. Urges ‘Modernized’ Treaty — Arms Control Association
• Strategic Arms Limitations Talks/Treaty (SALT) I and II — Office of the Historian, U.S. Department of State
• United States Declines to Renew USMCA at First Joint Review — IISD

Part of the brossi.us reference library, written for readers of Dr. Bart Rossi, PhD. Last reviewed October 2026.