While it is no doubt a humanitarian tragedy and innocent people are being killed, it is not in the long-term strategic interests of the United States or the American People for our nation to support the Syrian rebels or be involved in what is an internal Syrian civil war.
Bashar al-Assad is a brutal dictator, but as we have seen in Egypt and Libya the so-called democratic revolutions are not citizens crying out for and implementing Jeffersonian democracies, but rather revolutions driven primarily by radical Islamic fundamentalism and led by the Muslim Brotherhood whose ultimate goal is the establishment of Islamic states and a Middle East-wide Muslim caliphate.
In summary, establishment radical Islamic states are not in our strategic interest and we should not enable it to occur.