I'll say it again but in a much bolder tone: A unilateral attack on Syria sets the U.S. up for a very hard and bloody fall.
Yes, ultimately this is Syria's problem and yes, President Obama's "redline" has been passed, but I think the American people deserve to know concretely if the use of chemical weapons was sanctions by the Syrian government and, if so, we WILL need international support to take military action. Without both, we could be in way over our heads especially if Russia, China, Iran and NKorea all get involved.
Trust me when I say you don't want the U.S. to go this alone.
"A fair exchange ain't no robbery." Tupac Shakur w/Digital Underground
If congress says no:
1) Obama can still assert that after many months of dragging his own feet (leading from behind?) that he "always" wished to "do something" about Syria even though he never sought the advice of congress before.
2) Congress (emphasis will be naturally limitted to the GOP members) is to now to blame if anything "bad" happens in Syria since he wanted to act and congress "stood in his way" by denyinig Obama's wish to attack.
3) If, by some miracle, things calm down in Syria Obama can assert that was due to his "stern resolve" to use U.S. military force if necessary.
If congress says yes:
4) If the Syria attack works out OK then Obama can say that he initiated the bold miltary action resulting in "peace".
5) If Syria goes badly then Obama can still say it was either due to (GOP) congressional resistance to his having taken quicker action - or simply not bringing up the fact that it was basically his idea at all.
“The reasonable man adapts himself to the world: the unreasonable one persists to adapt the world to himself.
Therefore all progress depends on the unreasonable man.” ― George Bernard Shaw, Man and Superman