WASHINGTON -- At a recent closed-door congressional briefing on the administration's new strategy to combat the Islamic State, a top CIA official left little doubt among those in the room about the agency's attitude toward the project.

The official's muted approach to the briefing dovetails with what senior intelligence community officials tell The Huffington Post is deep behind-the-scenes skepticism, ranging from ambivalence to outright opposition, from within the CIA to the administration's proposal to task the Department of Defense with arming the so-called moderate Syrian rebels.

The opposition derives from a number of factors. First, the CIA has already been covertly equipping Syrian rebels at the instruction of the White House, but has come to find the fighters increasingly disorganized and radicalized as the conflict goes on, with U.S.-supplied arms winding up in the hands of more radical fighters.

Meanwhile, some turf issues are at play. While officials in the CIA are skeptical of the broader strategy to arm and train the rebels, they are also wary of a plan that would give the Pentagon a responsibility that has so far rested with their agency.

One Democratic member of Congress said that the CIA has made it clear that it doubts the possibility that the administration's strategy could succeed.

"I have heard it expressed, outside of classified contexts, that what you heard from your intelligence sources is correct, because the CIA regards the effort as doomed to failure," the congressman said in an email. "Specifically (again without referring to classified information), the CIA thinks that it is impossible to train and equip a force of pro-Western Syrian nationals that can fight and defeat Assad, al-Nusra and ISIS, regardless of whatever air support that force may receive."

He added that, as the CIA sees it, the ramped-up backing of rebels is an expansion of a strategy that is already not working. "The CIA also believes that its previous assignment to accomplish this was basically a fool’s errand, and they are well aware of the fact that many of the arms that they provided ended up in the wrong hands," the congressman said, echoing intelligence sources.

CIA spokesman Ryan Trapani disputed the validity and accuracy of those assertions.

The CIA has been training the Free Syrian Army out of covert bases in Jordan, The Washington Post reported last year. The operation is something of an open secret. As Congress debated whether to launch airstrikes against Assad last year, staffers with the House Foreign Affairs Committee asked the House Intelligence Committee whether the agency was working rebels on the ground. "They said, 'We can't tell you that,'" said a Hill aide.

But the White House is now asking Congress to authorize the Defense Department to take over and expand the training operation under what's referred to as Title 10 authority.

“That would be a DOD operation as opposed to a CIA operation, and so when you’re talking about arming the Free Syrian Army … we’d be able to be more public about it,” Sen. Kelly Ayotte (R-N.H.) told The New York Post last week.

Ben Rhodes, the White House deputy national security adviser, made a similar argument.

"What the Title 10 authority allows you to do is ... to be public about what you're doing, which is, frankly, I think, a healthy way to do it in the first place," he told HuffPost. "So giving this kind of authority to the Pentagon allows you to describe your policy and describe who you're working with and have robust oversight of it, so that's one thing it allows."

"We have been working with the Syrian opposition now for a couple of years, providing them assistance -- non-lethal at first, but them we provide them with some military assistance," Rhodes said. "So we know them better today than we did a year, two years ago. There are people who have been vetted, you know, who we have relationships with, who we deliver assistance to, so we're not starting from scratch."

Bringing in the Pentagon, Rhodes said, "does allow you to scale up your training and equipment, so if you have this kind of program that the military can participate in, you can just do things on a bigger scale."

HuffPost interjected: "Than the CIA."

"Your words, but yeah," he said, nodding. "It allows for us to structure this with the regional partners in a more systematized way, so that essentially you have the training program, with Sunni Arab partners doing a lot of the training."

“CIA supports and is working with the Defense Department and all our U.S. Government partners in the fight against ISIL," Trapani, the CIA spokesman, told HuffPost.

Since President Barack Obama announced scaled-up plans for arming and training Syrian rebels, an idea he himself criticized as recently as last month, military and administration officials have been briefing lawmakers on the specifics. Some have been persuaded by plans to ramp up the Defense Department's role. "It was instructive," Rep. Adam Schiff (D-Calif), a member of the House Intelligence Committee, told HuffPost last week. "General Dempsey did a good job laying out the military dimension."

Other lawmakers have not been won over. And on Tuesday, Washington Post columnist David Ignatius, who is known to have close source relationships with top intelligence officials, proposed giving the CIA command over the training program, rather than the Pentagon.

One idea that has received less public debate but is being pushed by some in the CIA would be to covertly ally with Syrian President Bashar Assad against the Islamic State -- in an enemy of my enemy pact -- rather than lean on the rebel groups.

Rhodes adamantly dismissed the idea in the interview. But according to some reports, Assad is expecting the U.S. to come around. "The regime recognizes that the Western opening will be in secret, and via security channels and not diplomacy. The political-diplomatic opening needs longer," Salem Zahran, a Lebanese journalist with close ties to the Syrian government, told Reuters in August. "But the regime believes that the whole world will come to coordinate with it under the slogan 'fighting terrorism'."

Some covert cooperation is already underway, according to a recent report by Haaretz. "Western diplomatic sources admitted Monday morning that despite the sweeping denials and the United States’ declared opposition there is intelligence cooperation between Damascus and Washington," the Israeli paper reported. "According [to] a report in the Syrian newspaper Al-Watan Monday, the cooperation is conducted through an unnamed third party and is not direct."

Secretary of State John Kerry also kicked off speculation about cooperation between the U.S. and Assad with a rather conflicted denial that such coordination was happening. "No, we're not going to coordinate with Syria," Kerry said on CBS's Face The Nation. "We will certainly want to deconflict to make certain that they're not about to do something that they might regret even more seriously. But we're not going to coordinate."

Reporters subsequently failed to elicit a definition of "deconflict" from a State Department spokeswoman, but it is a military term that refers to competing forces monitoring each other's movements so as to avoid coming into contact.

Making a deal with Assad would give the U.S. more leverage in nuclear talks with Assad's allies in Iran, and could also play into negotiations over a resolution of the Ukraine crisis. Assad is a client of Russia, which intelligence analysts say may be willing to make concessions in Ukraine in exchange for preserving Assad in power.

The House is expected to vote Wednesday on the plan to have the Pentagon arm the rebels.