Middle East In northern Syria, is the US running out of rebel allies?

Harakat Hazzm, a US-armed group vetted by the CIA for training, has fallen to an Al Qaeda affiliate that is targeting moderate rebels. 

Edlib News Network/AP/File

Gains by Jabhat al-Nusra, an Al Qaeda affiliate, have forced two major US-backed rebel groups to disband at a time when Washington needs solid partners to counter the influence of jihadists in Syria.