Rebel groups based in southern Syria are advancing on the western suburbs of Damascus and warning they might soon enter the capital, a development that’s in sharp contrast to the grim reports from northern Syria, where moderate rebels have suffered setbacks from the government and radical Islamists.

The advance by the so-called Southern Front also stands apart from the situation in the north because moderate rebels still appear to be the dominant opposition force in the south, eclipsing al-Qaida’s Syrian affiliate, the Nusra Front, in planning and executing military advances.

Further, Southern Front commanders credit airstrikes by the U.S.-led coalition with helping their cause, primarily by keeping Islamic State fighters from moving against them. “If it weren’t for the coalition strikes, Daash would have reached our areas,” Abul Majd, a spokesman for the Southern Front, told McClatchy via Skype, using the Arabic acronym for the Islamic State. “Thanks to these strikes, we are focusing now on the regime, our main enemy.” […]