Presidents have more power and responsibility in foreign and defense policy than in domestic affairs.
They are the commanders in chief of the armed forces; they decide how and when to wage war. As America’ chief diplomat, the president has the power to make treaties to be approved by the Senate. And as head of state, the president speaks for the nation to other world leaders and receives ambassadors.
Presidents almost always point to foreign policy as evidence of their term’s success. Congress—as long as it is consulted—is less inclined to challenge presidential initiatives in foreign policy than in domestic policy. The idea that the president has greater autonomy in foreign than domestic policy is known as the “Two Presidencies Thesis.”
The President and Waging War
The President is the Commander-in-Chief of the United States Armed Forces and as such has broad authority over the armed forces. However, only Congress has authority to declare war and decide the civilian and military budget.
War powers provide a key avenue for presidents to act in foreign policy. After the 9/11 attacks, the Office of Legal Counsel argued that as commander in chief the President could do what was necessary to protect the American people. Since World War II, presidents have never asked Congress for (or received) a declaration of war. Instead, they relied on open-ended congressional authorizations to use force, United Nations resolutions, North American Treaty Organization (NATO) actions, and orchestrated requests from tiny international organizations like the Organization of Eastern Caribbean States.