The government of President Bashar Assad is the legitimate and legal government of Syria whether the U.S., Israel, or Sen. John McCain, R-Ariz., like it or not. If we are going to take over the war on behalf of the rebels, if we haven't already, then we should follow our Constitution and demand that Congress declare war against the nation of Syria. As our policy now seems to be to take a military role in every dispute between Shiite and Sunni, we should declare our side before we intervene under the sham of Democracy, which neither side really wants.
The rebels we are or will be supporting are mainly Sunnis, the majority sect that are oppressed by the Assad regime, which is mainly Alawite Shiia. It is reported that among the rebels are al-Qaida and other factions, none of which offer a more liberal future for Syrians.
There were three options for the U.S. and NATO: support the Assad government and prevent the horrific loss of life, refugee plight, and destruction of infrastructure; oust Assad with overt military intervention and hope the new regime isn't worse yet; stay out altogether.
The second option would result in permanent U.S. military presence, furthering McCain's vision of war with Iran. That would be the ultimate disaster for all.