Congress possesses major constitutional tools. It declares war, raises and supports armed forces, makes rules for them, regulates foreign commerce, enacts sanctions, and controls appropriations. The Senate provides advice and consent on treaties and specified appointments. Congress can also require reports, investigate execution, and condition funds. A treaty requires approval by two-thirds of senators present before ratification; a congressional-executive agreement rests on legislation; and an executive agreement must rest on presidential authority, delegated authority, or both. These routes are not interchangeable labels for any international promise.

War powers illustrate recurring institutional conflict. As commander in chief, the president directs military operations and can respond rapidly. Congress controls long-term funding and important legal authorizations. The War Powers Resolution establishes consultation and reporting requirements and a statutory framework for the continued use of forces in hostilities, although presidents and Congress have disputed parts of its application. A declaration of war, an authorization for use of force, an appropriation, and a tactical military order perform different legal functions.

Suppose the president deploys forces during an emergency while Congress holds hearings, debates an authorization, and considers whether to continue funding. The president initiated operations through executive and military authority; Congress uses legislative, fiscal, and oversight powers to shape continuation. The scenario demonstrates shared authority, not proof that either branch possesses every foreign-policy power. Durable results also depend on agencies, allies, adversaries, administrative capacity, and public support, so legal adoption and international effectiveness remain separate questions.

Video lesson: Introduction to the public policy process | US government and civics | Khan Academy