Foreign policy is the arena where the President's power is greatest. The Supreme Court has described the President as the nation's primary voice in foreign affairs, and Presidents can act quickly through diplomacy, executive agreements, and military deployments. But Congress holds the purse, writes the laws on trade, sanctions, and immigration, and can shape or constrain policy.
This guide explains who makes foreign policy and how the pieces fit together.
Article II makes the President commander in chief, empowers the President to make treaties with the Senate's consent, appoint ambassadors, and receive foreign ambassadors. Article I gives Congress the power to declare war, regulate foreign commerce, set tariffs, raise and fund the military, and define offenses against the law of nations. The Supreme Court called the President the sole organ of the nation in foreign relations in United States v. Curtiss-Wright in 1936, and in Zivotofsky v. Kerry in 2015 it held that the President alone decides which foreign governments to recognize.
Congress shapes foreign policy through appropriations for the military, diplomacy, and aid, through laws on sanctions, arms sales, and trade, through Senate confirmation of ambassadors and officials, and through treaties. The Senate Foreign Relations and House Foreign Affairs committees hold hearings and write authorization bills. Congress has imposed sanctions over presidential objections, as with the 2017 Russia sanctions law, and can block arms sales by joint resolution, though such resolutions face vetoes.
The Defense Department, with forces and bases around the world, is the largest foreign policy actor by budget. The intelligence community informs decisions and conducts covert action under presidential findings reported to Congress. The Treasury's Office of Foreign Assets Control administers sanctions, the Commerce Department controls exports of sensitive technology, and the Trade Representative negotiates trade deals. Foreign aid, now largely run by the State Department, supports health, development, and security goals.
The Secretary of State, the senior cabinet officer, leads the State Department, which runs embassies and consulates, negotiates agreements, issues visas and passports, and represents the country at the United Nations and other organizations. Ambassadors are confirmed by the Senate, and about 30 percent have traditionally been political appointees, often donors, with the rest career Foreign Service officers. In 2025 the department was reorganized, about 1,350 employees were laid off in July, and USAID's remaining programs were moved into the department.
The National Security Council, created in 1947, brings together the President, Vice President, and the secretaries of state, defense, and treasury, with the Director of National Intelligence and Chairman of the Joint Chiefs as advisers. The National Security Advisor manages the process, and its staff coordinates policy across agencies. Presidents vary widely in how much they rely on the formal process, and the NSC staff was cut significantly in 2025.
Supporters of strong presidential leadership say the country needs to speak with one voice, act quickly, and keep diplomatic secrets. Critics argue that Presidents have taken over powers the Constitution gave Congress, especially over war and trade, and that policy now swings sharply between administrations. Debates over the 2025 changes pit those who say diplomacy and aid had become bloated and unaccountable against those who warn that cuts weaken American influence and leave room for rivals such as China.
See how international deals are made in treaties and executive agreements, learn about the use of force in war powers: who decides to go to war, or see the coordinating body in the National Security Council explained.