I do not believe that the US will intervene in Syria under any circumstances, although Obama is compelled to make statements as he has recently to attempt to forestall Syria's use of chemical weapons. I have pointed out elsewhere that the US, having destroyed its own stockpiles of chemical weapons (almost 30X those of Syria) which dated to WWI, has the technical capability to dispose of the problem safely if given the opportunity.
IMHO, the threat of a Chemical Weapons Usage by Syria has greatly increased with foreign intervention. Syria is suffering from an insurgency that is only partially domestic, and armed and funded externally to a very large extent. Not only that, many of the combatants are not even Syrian. They are entering Syria from Turkey. Turkey is using the umbrella of NATO to carry out sabotage in a neighbouring country in complete transgression of international laws. More than 23,000 Syrians have lost their lives, and given the flow of funds and weapons from Turkey, Saudi, Qatar, US, and elsewhere, the rebels have consistently rebuffed any attempts to negotiate. Turkey is at the forefront of this insurgency. Under such circumstances, Turkey is a legitimate target for Syria to use its Chemical Weapons.
Personally, I feel Assad has shown great restraint in not using its Chemical Weapons. This war has been imposed upon him, and no matter what he does, he is well within his rights to defend his country, and the primary responsibility lies with Turkey.
Obama, for a change, could spend some time reading the US Constitution. The same applies to the US military generals, especially that obnoxiously outspoken Leon Panetta. The sooner the US goes back to the fundamentals, i.e., a non-interventionist foreign policy, the better will it be for the US. Sadly, these days, the US Constitution is forgotten in the midst of a lot of seemingly patriotic ruckus.
Please don't take this personally, but any act by anybody, no matter how dangerous, or how brave, deserves zero credit, if it does not uphold the constitution. A person is a citizen first, and soldier second.