According to the latest poll, only 9% of Americans think the US should intervene in Syria, with 60% affirmatively opposed to intervention. (See here: http://www.washingtonpost.com/blogs/worldviews/wp/2013/08/26/new-poll-sy...)
An attack on Syria would not only bring Syrian retaliation and further destabilize the region, but could draw two of Syria's major allies into the conflict as well: Iran and Russia. In the best case scenario, the U.S. removes the Assad regime from power, leaving control of the country in the hands of rebels who identify with Al Qaeda.
Intervention in Syria is unequivocally a no-win scenario for the U.S.