[Muser]

Quote by: Winter wind I've asked you about this before. Which war powers and emergency act?

This article provides a good synopsis.

Congressional concern about Presidential use of armed forces without congressional authorization intensified after the Korean conflict. During the Vietnam war, Congress searched for a way to assert authority to decide when the United States should become involved in a war or the armed forces be utilized in circumstances that might lead to hostilities. On November 7, 1973, it passed the War Powers Resolution (P.L. 93-148) over the veto of President Nixon. The main purpose of the Resolution was to establish procedures for both branches to share in decisions that might get the United States involved in war. The drafters sought to circumscribe the President's authority to use armed forces abroad in hostilities or potential hostilities without a declaration of war or other congressional authorization, yet provide enough flexibility to permit him to respond to attack or other emergencies. The record of the War Powers Resolution since its enactment has been mixed, and after 30 years it remains controversial. Some Members of Congress believe the Resolution has on some occasions served as a restraint on the use of armed forces by Presidents, provided a mode of communication, and given Congress a vehicle for asserting its war powers. Others have sought to amend the Resolution because they believe it has failed to assure a congressional voice in committing U.S. troops to potential conflicts abroad. Others in Congress, along with executive branch officials, contend that the President needs more flexibility in the conduct of foreign policy and that the time limitation in the War Powers Resolution is unconstitutional and impractical. Some have argued for its repeal.