He also points to the lack of coordination among rebel groups, the claims of the Free Syrian Army leadership notwithstanding. "Rebel coordination rarely extends beyond neighboring towns and villages and never to the provincial or national level. Many rebels don't even know the commanders in towns two hours away."
The presence of hardcore Islamists, some of whom were veterans of the wars in Iraq and Afghanistan against the US, was an issue in the Libyan civil war, as was weak levels of coordination between regionally based rebel commanders. But Libya is a fairly religiously homogeneous country in a much more stable neighborhood.
In Syria, the civil war is already heavily tinged by sectarian issues – with the governing minority Alawites squared off against the Sunni majority, with the country's Christian population watching nervously from the sidelines. The country shares borders with Iraq and Lebanon – which have suffered sectarian bloodletting of their own in the recent past – as well as Israel.
The difference between providing weapons yourself and merely directing who gets them is a vanishingly slim one – so slim that the jump from the latter to the former is an easy one to make. While the US isn't there yet, it's inching closer. US arms flows and support to the mujahedin fighting the Soviet Union in Afghanistan in the 1980s and the South Vietnamese in the 1950s all began with a trickle.