Vietnam War: A long, costly armed conflict that pitted communist North Vietnam against South Vietnam and its main ally, the United States; one reason why War Powers Act was enacted.
Separation of Powers: An act of vesting legislative, executive, and judicial powers into separate bodies so no single entity has absolute control; underpins concept behind War Powers Act.
Congressional Approval: The approval needed from both houses (Senate & House) for certain actions such as declaring war; central aspect of War Powers Act.