These are the people we would empower by intervening in Syria. From a front-page article in today's New York Times:

"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.

"This scene, documented in a video smuggled out of Syria a few days ago by a former rebel who grew disgusted by the killings, offers a dark insight into how many rebels have adopted some of the same brutal and ruthless tactics as the regime they are trying to overthrow."

You cannot have it both ways. You cannot say we must intervene in Syria because of atrocities committed by the regime against its people, and ignore the fact that doing so would help tip the scales in favor of men who are committing other atrocities against a different group of Syrians. I'm pretty sure the summary execution of prisoners of war also violates international norms.

And to those who object that chemical weapons are a horse of a different color, here's another account of the evolution of the Free Syrian Army, from Foreign Policy (subscription required; h/t: Hot Air):

"On August 22, four of the five front commanders threatened to resign from the SMC [Supreme Military Command], promising to break 'red lines' and work 'with all forces fighting in Syria,' a clear reference to the war's growing Salafist-Jihadist contingent. The statement was read by Colonel Fatih Hasun, who is the commander of the SMC's Homs Front and the deputy chief-of-staff, that is to say, [FSA leader Gen. Salim] Idriss's deputy and the most senior officer inside the country. Hasun added that rebels would no longer respect demands by outside powers that they not attempt to take over government-controlled chemical weapons sites. In addition to demanding action in response to the government's use of chemical weapons in Damascus, Hasun also demanded better weapons and said they were tiring of the 'false promises of those who call themselves Friends of Syria.'

"While the resignation seemed tentative, Hasun was less equivocal about the other red line -- the opposition's Salafist-Jihadist groups, Jabhat al-Nusra and the Islamic State of Iraq and al-Sham (ISIS) -- both of which the United States has designated as terrorist entities linked to al Qaeda. Directly behind Hasun on the wall was an Islamic flag, with a pre-Assad Syria FSA flag draped to the side, a nod perhaps to the Salafists. Sitting to his right was a bearded cleric in Salafist garb. He directly stated, 'we call upon all' FSA units to work with all others fighting the regime. Adding insult to injury, on August 25 Muhammad Tabnaja, field commander in Latakia for the Ahfad al-Faruq Brigade in Latakia, resigned citing the lack of support from the SMC." (emphasis added; link original)

Both of these accounts are of a piece with other descriptions of a rebel army that is being overrun by jihadis who make up a minority of the troops but increasingly are the best armed and most powerful fighting forces.

If the U.S. goal is to prevent proliferation of chemical weapons and send a message that their use will not be tolerated by the international community, it is far from clear that strengthening the hand of the rebels is -- at this point in time -- a viable way of doing that. Again, you cannot have it both ways. This is the same mistake we have made in past military engagements; arguably, the only one that has not has this result was Iraq, and I know of few people ready to repeat that kind of long, deep commitment.

If President Obama's bottom-line wish for Syria is to help the most moderate elements of the Syrian opposition gain power, it's probably a noble one. It might even be one that a majority of Americans would support. But that is a far cry from what he has actually asked Congress to authorize in terms of military action, and it would probably entail a deep involvement that neither Congress nor the public is likely to support. We will not be able to degrade the Assad regime and its military, and also root out the extremists from the rebel forces, with the "limited" action Obama has promised. So what would we really accomplish?