Earlier this year, the CIA concluded that arming the rebels with small-scale weapons—what is likely now being considered—could not tip the balance of the conflict. U.S. and Israeli officials still fear that delivering anything larger or more lethal, such as antitank or surface-to-air missiles, could be used on U.S., Israeli, or commercial targets if they fell into terrorist hands. Chris Dougherty, an expert at the Center for Strategic and Budgetary Assessments in Washington, says the "ideal" weapons to arm the Syrian opposition groups—such as man-portable air-defense systems (MANPADS) that could counter the Syrian Air Force's control of the skies, antitank guided munitions such as the FGM-148 Javelin, and GPS- or laser-guided mortar rounds—are also the weapons that "have the most potential for blowback."
"Right now, it seems as though the influx of foreign weaponry (e.g., Unmanned aerial vehicles from Iran), increased involvement from Hezbollah, and more effective tactics have allowed the Syrian military to isolate the rebel groups into urban pockets before defeating them in detail," says Dougherty. "Giving the rebels improved anti-tank and anti-aircraft weapons would allow them to counter-attack the heavy forces that are hemming them in. It appears as though the regime has also compromised the rebels' communications networks, so secure radios could help them coordinate operations without giving the regime advanced warning.
"By themselves, however, these systems are unlikely to turn the tide back in favor of the rebels," Dougherty adds. "Syria has a large, relatively well-armed military that seems to have learned some lessons from its initial setbacks." He says "the most effective support the United States and its allies could give the moderate groups would be unconventional warfare training and advice from special operations forces."