As sad as it may seem, the necessary thing for Obama to do is take action in Syria, if only to save face after establishing the arbitrary “red line” of chemical weapons.
There is nowhere to go but down in this conflict, and certainly a few days of targeted bombing will not bring down the Assad regime. But the goal of intervention can’t be to topple Assad unless we are willing to send in ground troops to establish post-Assad peace, which is clearly impossible.
The civil war needs to play itself out, and sending a message to punish Assad with a targeted bombing campaign is the least worst interventionist option. Doing nothing is not an option, as the credibility of the US is on the line. No reasonable person can expect a decisive outcome from an air attack, and nobody should. The US must stand by its word; get in and get out with an air campaign and let the war play out. If things escalate via Syrian or Iranian retaliatory strikes against Israel or US targets in the region, we reevaluate at that time.