Like with economic sanctions there but do it with a coalition, that includes America, Canada, the European Union and the Arab League. As well as sending in a military force that could include, Turkey, perhaps Israel, the Arab League and maybe even the European Union. Not to take down the Assad Regime and wipe out it's military. But to provide protection and cover for the democratic protesters there, to prevent violence and to defend the protesters there. And the American military could assist in a way not with troops or planes or ships, but with resources and equipment to whatever international coalition that would develop to protect the Syrian people from unfortunately their own government.
As well as we could essentially bribe members of the Assad Regime and it's military to defect from that Regime, including President Assad himself. And get an agreement with the Syrian opposition to not prosecute, or punish whoever were to defect from the Assad Regime once they were to take power. We could help push the Assad Regime out-of-power and to make room for a new democratic government, or a transitional government to start off there. Similar to what's going on in Egypt until they elect a new government with peaceful means.
The last thing that America needs to do is get involved in another war, as far as committing more troops, bases, tanks, planes, ships, etc. Especially since we are currently paying for two wars that we can't afford by borrowing all the money. But what we can do is assist others in doing this to promote a peaceful resolution in Syria and bring the Assad Regime down.