Wouldn’t congressional refusal make the United States look weak, as critics including Senator John McCain warn loudly? Hardly. The next dictator who acts rashly will face a different situation and a different calculus. The UN Security Council or NATO may feel differently about the need to act. There may be a new threat to American interests that lets Obama or the next president offer a different justification for acting. It just won’t matter very much what Obama said about red lines in the past. World leaders say provocative things all the time and then ignore them. Their motto is: That was then, and this is now.

If Congress turns him down, won’t Obama be undermined at home, as other critics claim? In what sense? It is hard to see how the Republicans could be less cooperative than they already are. And it’s not in the interest of Democrats to fault a president of their own party for acceding to what Congress wants instead of acting unilaterally.

Some commentators argue (or hope) that whatever happens, Obama’s request for military authorization will be an important precedent that will begin to restore the constitutional balance between the president and Congress in the area of war powers. Don’t bet on it. By asking for congressional authorization in this case, Obama has not ceded any authority that he ­or any other president ­has previously asserted in war powers.

Syria presents a case in which previous precedents did not apply. There is no direct threat to American security, American personnel, or American interests. There is no Security Council resolution to enforce. And there is no claim that America needs to shore up the credibility of NATO or another important security alliance. Nor does Obama have even the feeble justification that the Clinton Administration offered in Kosovo­: that congressional appropriations midway through the operation offered tacit and retroactive approval for the bombings.



It is naive to think that the next time a president wants to send forces abroad without congressional approval, he or she will be deterred by the fact that Barack Obama once sought congressional permission to bomb Syria. If a president can plausibly assert that any of the previous justifications apply -- ­including those offered in the Libya intervention -- the case of Syria is easily distinguishable.



Perhaps more to the point, Congress still cannot go to the courts to stop the president, given existing legal precedents. Congress may respond by refusing to appropriate funds, but that is a remedy that they have always had -- and have rarely had the political will to exercise.



The most important limit on presidential adventurism is political, not legal. It will turn less on the precedent of Syria than on whether the last adventure turned out well or badly.



In fact, the Syria episode offers Obama­ and future presidents­ new opportunities for increasing presidential power. Obama has submitted a fairly broad authorization for the use of military force (AUMF) proposal to Congress. It is not limited either temporally or geographically; it does not specifically exclude the use of ground troops; and it requires only that the president determine that there is a plausible connection between his use of force and the use of weapons of mass destruction in the Syrian civil war. If Congress adopts this proposal, President Obama ­and every future president ­can simply add it to the existing body of AUMFs and congressional authorizations.



In the American system, presidents often gain the most power not by acting unilaterally or in defiance of congressional statutes but by relying on previous congressional authorizations and interpreting them generously to expand their authority­ -- sometimes in ways that Congress never dreamed of. A case in point is the 2001 AUMF against al-Qaeda, which has no time limit. It has served as the justification for a wide range of executive actions by Presidents George W. Bush and Obama, and it will probably to continue to do so well into the future. That is a good reason to amend Obama’s proposal for a new AUMF to include a sunset clause, a geographical restriction, and a limit on what kinds of forces can be used.