For the last month, the media and Congress have been grilling the State Department for the security failures during the deadly assault on a U.S. compound in Benghazi, Libya. But what if the State Department is the wrong target of scrutiny?

According to a counter-theory advanced last night by The Washington Post's Dana Milbank, the CIA, not the State Department, bears some responsibility for the security lapse that led to the death of Ambassador Chris Stevens and three other Americans, but is flying under the radar due to the classified nature of its activities there.

The airing of this theory was prompted by yesterday's House Oversight and Government Reform hearing, in which House Republicans attempted to avoid any mention of CIA activities in Benghazi. As it happened, they failed to avoid veiled disclosures of CIA activities from emerging, and the way Milbank sees it, they "left little doubt" that one of the two U.S. compounds in Benghazi was in fact a CIA base. 

In their questioning and in the public testimony they invited, the lawmakers managed to disclose, without ever mentioning [the CIA] directly, that there was a seven-member “rapid response force” in the compound the State Department was calling an annex.

The disclosures came out in a vague sort of way that mostly only Washington experts would realize. For instance, one of the State Department officials revealed that not all of the security personnel in Benghazi "fell under my direct operational control." Who controlled them? An entity members of the hearing described as the "other government agency," which is a typical Washington euphemism for CIA. 

From there, Milbank unveils his theory. "Republicans were aiming to embarrass the Obama administration over State Department security lapses. But they inadvertently caused a different picture to emerge than the one that has been publicly known: that the victims may have been let down not by the State Department but by the CIA," he writes. 

The shifting of blame from the State Department to the CIA would, indeed, be quite the unexpected development. We contacted the CIA but the agency declined to comment on Milbank's allegations.

So here's what we know about its activities in the area. According to a September 23 New York Times report, of the two dozen U.S. personnel evacuated from Benghazi in wake of the attacks, about a dozen were CIA operatives and contractors "who played a crucial role in conducting surveillance and collecting information on an array of armed militant groups in and around the city." These duties included tracking down leftover shoulder-fired missiles from Qaddafi's forces, securing chemical weapons stockpiles and helping train Libyan spies.

It's certainly an interesting wrinkle to our understanding of the U.S. presence in Benghazi, but the CIA's alleged culpability is not as clear cut as Milbank makes it sound. 

For instance, which government entity was ultimately responsible for security? Did State take the lead on security? Did the CIA? Or was it a mix? During yesterday's hearing, a State Department official suggested some sort of combination, noting: "Not necessarily all of the security people" fell under State Department control. It's not clear if we'll ever know the answer to this given the classified nature of the CIA's activities. But one group of people will know: Members of the Congressional committee. In a rather blunt statement, committee chairman Darrell Issa alluded to talking about the sensitive details about the U.S. presence later: "The entire committee have a classified briefing as to any and all other assets that were not drawn upon but could have been drawn upon” in Benghazi, he said. I guess it's left up to them to get to the bottom of this. Who's betting they will?