I support air support from America if the Syrians use sarin gas on it's population. We should not get involved up to that point. There are plenty of freedon fighters in Syria to do the ground combat. There is no need to send our troops into that country.
With precision munitions aimed at Seria's military the revolution there would be over in a matter of a couple of weeks.
What we would need is some varifyiable assurance that we could go in and remove the chemical weapons the minute the rebels won the ground war and have taken over the government. Russia still makes any U S involvement tricky but we could work something out with them prior to adding our air muscle to the Serian people's cause.
There's no margin for errors.
Delivery systems of Syria have to be taken out by one "simultaneous" strike.
And this only the US can do, and I think US has to do it alone because a possible first-strike by a "group of nations" is too much coordination efforts and a first strike is better done through US Army's own command-hierarchy.
What comes after such possible "first strike"-scenario is another thing.