It's public knowledge now that the U.S. mission in Benghazi was "at its heart" a CIA operation, and there is evidence that U.S. agents—particularly murdered ambassador Chris Stevens—were aware of heavy weapons moving from Libya to Syrian rebels.

But don't expect an confession from the CIA or the Obama administration.

"The CIA can't admit their role because it compromises the cover of the facility, and that's the most important thing," Bob Baer, who spent two decades as a field officer in the CIA, told the Huffington Post. "You can never compromise cover."

Since most of the Syrian opposition's weapons are being handed out by the CIA, it would make sense that the heavy weapons that rebels are now using to shoot down regime aircraft came from a covert CIA operation.

The exposure of such an operation would raise serious issues since transferring arms to anyone associated with al-Qaeda—which may include some of the best fighters among the Syrian opposition—would violate a binding UN arms embargo that prohibits arms transfers by UN member states to countries or groups including al-Qaeda.

The Obama administration is equally hamstrung because any admission of gun-running would would validate Russia's long-held position that it is arming radicals in Syria.

For months Russia has accused the U.S. of providing support to "terrorists" to topple the government in breach of international law, and recently a top general recently claimed that the U.S. was “coordinating” deliveries of arms—including U.S.-made anti-aircraft missiles—to Syrian rebels.

The State Department contends that the U.S. is not directly providing any lethal assistance to the rebels and that the only heavy weapons seen in Syria were “Soviet vintage.”

That argument is technically true but increasingly weak since most of the weapons going to jihadists in Syria are U.S.-made and the heavy weapons that traveled from Benghazi to Turkey are Soviet-era missiles taken from Libyan government arsenals after the Libyan revolution.

In short, if a covert U.S. operation to divert heavy weapons from Libya to Syrian rebels is now exposed, it would be an international black mark on the U.S. government and its spy agency. But you probably won't hear that from them.

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