Koh argues that if there's no longer a connection between the war and the basis for the 2002 authorization of force, or the 2001 authorization of force to fight terrorist groups that followed 9/11, then the war in Iraq could already be unauthorized. "The authorizations are being treated as permitting any mode of escalation so long as the war on terror is going on," he says. Instead, Congress should require the president "to have specific authority for specific action." And the framework for that discussion, Koh says, should be the War Powers Resolution. The 1973 law states that unless Congress says otherwise, the troops must come home within 60 days after the president "reports" that he has engaged in hostilities. (The president can extend the deadline for 30 more days to "protect and remove" them.) The War Powers law is often derided as weak, and the courts haven't definitely ruled on whether it's constitutional. But it's a potential tool that Congress could try to get more out of than it has so far.