NYT:

"The Syrian rebels posed casually, standing over their prisoners with firearms pointed down at the shirtless and terrified men.

The prisoners, seven in all, were captured Syrian soldiers. Five were trussed, their backs marked with red welts. They kept their faces pressed to the dirt as the rebels’ commander recited a bitter revolutionary verse.

“For fifty years, they are companions to corruption,” he said. “We swear to the Lord of the Throne, that this is our oath: We will take revenge.”

The moment the poem ended, the commander, known as “the Uncle,” fired a bullet into the back of the first prisoner’s head. His gunmen followed suit, promptly killing all the men at their feet."

There are numerous similarly brutal videos on YouTube and elsewhere, most notably was a video of an opposition rebel attempting to cut out and eat the heart of a dead soldier. However, as the Time's reporter C.J. Chivers notes, "many rebels have adopted some of the same brutal and ruthless tactics as the regime they are trying to overthrow."

The scene documented in the video, was smuggled out of Syria recently by a former rebel who had become disgusted by the killings, according to Chivers.

Given the same opportunity, would these rebels use chemical weapons against those they consider enemies? If that question can't be answered with near certainty, there shouldn't be any more discussion of a U.S. strike in Syria.