Even if you accept the one-sided version of the Syria conflict that Bashar al-Assad is evil incarnate and the rebels are heroically struggling against an oppressive regime...
President Barack Obama has failed to persuasively explain how bombing Syria prevents chemical weapons from being used again. Obama has attempted to get diplomatic cover for attacking Syria at the G-20, from the Arab League, at UN Security Council and from NATO. So far, Obama has failed to get a majority to even censure Assad.
Apparently, other countries noticed how UN Security Council resolutions criticizing Iraq got misinterpreted by the United States during the Bush administration.
If the goal is to keep poison gas from being used in Syria's civil war, I have a plan that I'm pretty sure will work. Of course, if the goal is to put the might of the U.S. military on the side of the rebels... well, that's a different project.
This proposal will probably require a UN Security Council resolution.
1. Install chemical weapons detectors in conflict zones across Syria.
2. Have UN military observers positioned around Syria.
3. Have the resolution refer allegations of chemical weapons use to the International Criminal Court. The jurisdiction would be limited to attacks after the resolution passes.
This would make it about impossible to use chemical weapons undetected.
It's not a perfect solution. But it is an improvement on the status quo. And it's a better solution than either bombing or joining the conflict on the side of the rebels.