The statute is called the War Powers Resolution, and it limited presidential power in response to the unpopular Vietnam War.32 The president may introduce armed forces only pursuant to (1) a declaration of war, (2) a specific statute, or (3) a national emergency created by attack upon the United States. The law also requires that the president report to Congress and withdraw troops after sixty days if there’s no formal authorization of war by Congress. But it hasn’t been enforced.
