A stalemate has set in between President Barack Obama and the U.S. Congress over the president's authority to initiate and continue combat operations against Libya. This should surprise no one. The limits on the president's constitutional authority to wage war are as uncertain today as they were when the Constitution was ratified. Complicating this uncertainty is that pesky law passed by Congress in 1973 over President Richard Nixon's veto: the War Powers Resolution (WPR).
Enacted in response to the widespread belief that it had become far too easy for a president to commit the nation to war, the WPR sought to revive congressional primacy in war-making decisions. The law had one clear objective: require express congressional approval before initiating hostilities in almost all cases. Accordingly, the WPR states that the president may lawfully commit U.S. forces into hostilities or into situations where hostilities are imminent only pursuant to a declaration of war, express statutory authorization -- like the post-9/11 Authorization for the Use of Military Force -- or an attack on the United States or its armed forces. The law also prohibits reliance on treaties, appropriation statutes or any other "implied" support to justify initiation of hostilities.
Contrary to widespread belief, the WPR does not give the president authority to wage war for 60 days. In fact, the law expressly indicates that nothing in the statute may be interpreted as a war authorization. Instead, in recognition that a president may initiate hostilities under good-faith assumptions that may turn out be false, the law requires termination of hostilities no later than 60 days after initiation absent express congressional endorsement.