MILNET: The War Powers Act of 1973
Congress, following the Vietnam War and further involvement in other country's conflicts, felt it needed more control over the Executive Branch and the power of the President in actions other than a Declared War.
The War Powers Act prohibits the President from waging war beyond 60 days *1 without Congressional approval. Authorization can be made in many forms such as a temporary waiver of the Act or via a Declaration of War.
In December of 1982, Congress, still not satisfied with the control
for support for the Contras who were getting U.S. support to overthrow
the government of Nicaragua, added an amendment, Boland
Amendment). See also the Hughes Ryan Act
of 1974 and the text of the act itself.
Some feel the War Powers Act serves to allow Congress the ability to enforce a pacifist, "sit-on-the-hands" approach to confrontation approach to world events as is illustrated by this paper (MILNET Mirror) by Timonthy S. Boyland and Glenn A. Phelps in 2001.