The reason that U.S. President Barack Obama passed the buck on authorizing a military strike on Syria to Congress is not because getting congressional approval is the constitutional thing to do. It always has been, although presidents have regularly denied it. Rather, Obama passed the buck to Congress because it was the only way out of the dilemma that he imposed on himself when he declared the use of chemical weapons to be a red line, without having thought through whether or how to go to war if the line was crossed.
When the red line was crossed, the administration’s belated search for military options faced two contradictions. The first was between the strong incentives to retaliate against the government of Bashar al-Assad and the wide opposition in both the United States and outside world to U.S. military action. The second was between the amount of force that would have a chance of producing useful strategic results and the amount that is politically tolerable. Even among those who demand action, pressure to use U.S. military power is exceeded by pressure not to use very much of it, for fear of entanglement that clearly does mean war.
A responsible choice for Congress and the president must at least be one that does not make things worse. All things considered, that could mean backing away from the threat of action so clearly implied by Obama weeks ago, even though that would be an embarrassing retreat. By accepting the embarrassment, those members of Congress who vote against authorizing the use of force can resolve the two contradictions. But those members who choose to back the president must also, in effect, endorse the intent to use modest amounts of force. That endorsement should, in principle, rest on a sober comparison of what all the potential strategies, including those already rejected out of hand, can be expected to accomplish at an acceptable price. What any strategy can do depends on the fit