The Syrian conflict is a sectarian war in a volatile region whose potential
to spread and directly threaten American interests would only be increased by
U.S. intervention.
The struggle is between forces funded and armed by outside sponsors, notably
Saudi Arabia, Qatar and Iran. Also participating are foreign religious groups
not directly controlled by the sponsors, namely the Sunni Salafists and
Iranian-aligned militias, not to mention intensely anti-Western al-Qaeda
fighters. American involvement would simply mobilize the most extreme elements
of these factions against the U.S. and pose the danger that the conflict would
spill over into the neighborhood and set Jordan, Iraq and Lebanon on fire.
That risk has been compounded by the recent Israeli bombing of weapons sites
inside Syria. Whatever their justification, the attacks convey to some Arabs the
sense that there is an external plot against them. That impression would be
solidified if the U.S. were now to enter the fight, suggesting a de facto
American-Israeli-Saudi alliance, which would play into the hands of the
extremists.
http://swampland.time.com/2013/05/08/syria-intervention-will-only-make-it-worse/