The button the Administration will likely push the hardest to get Congress to endorse a military strike is that the “credibility” of the US and (for loyal Democrats) of Obama is at stake; so is commitment to Israel and the “red line” against Iran.
The credibility of the United States is indeed at issue. Will we uphold or abandon commitment to international cooperation, to the conviction that seeking a level of consensus and collective action is the only way to move forward on the thorniest and most critical problems? Is there any hope for solutions or progress by going it essentially alone and showing the world once again the awesome power and ultimate futility of our military “option”? Not only regarding Syria, can progress be made on any big international problem by “red lining” the point at which we will give up on the process of collective political efforts and negotiation?
Another act of war can only deepen the trap we have dug ourselves into. There is terrible uncertainty about the immediate consequences of a military strike on Syria. But what about the longer term? Without the rest of the world, including China and Russia, can violence and human suffering be reduced? Can nuclear proliferation be halted and reversed? Can international law be sustained? Can we hope to cope with existential crises like climate change?