That the Assad regime is
brutal is not a surprise. Nevertheless, that does not mean that the U.S.
should intervene in Syria's civil war. Unless there is a compelling national interest, the U.S. should refrain from getting involved.
First, the anti-Assad elements have not offered any credible indications that they would initiate a tolerant political system, much less be able to maintain stability. Second, they have offered no credible assurances that they would embrace policies more compatible with U.S. interests (reduced cooperation with Iran, ending assistance to Hezbollah and Hamas, concluding peace with Israel, etc.).
Right now, one is witnessing a conflict in which the Sunni majority is seeking to topple the Alawite minority's hold on power. One cannot automatically draw the conclusion that a "democratic" revolution is underway. Indeed, some of the elements involved with the anti-Assad forces would argue against the idea of a democratic nature. Like most ethnic conflicts, the tactics employed by both sides are brutal, there's little inhibition about respecting the welfare of civilians, and the result is high casualties. Like most ethnic conflicts, there's also a zero-sum mentality held by both parties, neither of which is seriously interested in compromising on a peaceful path forward. Each side believes there is no mutually beneficial solution and that one can only gain at the expense of another. Each wants a total victory.
The experience in Libya and difficulties in Afghanistan and Iraq both argue for caution. Unpopular as it might be, unless there is a strong U.S. interest involved--and at present there isn't--the U.S. should refrain from getting embroiled in Syria's civil war. It should provide humanitarian aid and help Turkey deal with the refugee issue. If Syria begins to use chemical weapons against civilians as opposed to combatants, then an air strike against Syria's known chemical weapons facilities might make sense to take those weapons off the table. At this time, the limited evidence available does not reveal that the chemical weapons were deployed against civilians.