Yes, the US should get involved. Syria's Assad gov't is using chemical weapons on its own people - not only to stop that internal abuse, but also to prevent Syria from pointing those weapons on its neighbors and nearby communities. The question is how does the US do this while keeping the death toll at a minimum.
The best solution I can think of right now is to maintain diplomatic confrontation. Attacking Syria right now is attacking Syria's supporters, which include Russia, most prominently. Russia is probably only supporting Assad so long as Assad keeps signing checks over to them, but Russia also has an interest in maintaining the balance of power in the Middle East. If the US attacks Syria, Russia could enter on the side of Syria, or be dragged into it by supplying Assad during the conflict, or by attacking US forces on the periphery. If Russia is brought in, a domino effect would follow. This isn't a winning situation because other countries would be dragged into the conflict - over Syria.
On the flip side, the US could try to strengthen sanctions against Syria, which may benefit Russia in collecting more massive checks, but when the money dries up, Russia might just say fuck it and let the country drop off.
One thing that should happen is that the US prosecutes anyone connected to the sale of chemical weapons to Iraq back in the '80s. Then the US can call for equal prosecution against Putin and the entire Russian administration. Think the people in Russia wouldn't like that after the outcry they had from Putin's sham re-election? It would be a white revolution. All the US would have to do is sacrifice some shriveled white republicans who sold chemical weapons to Saddam Hussein.