A Free Syrian Army fighter stands beside a machine gun on one of the front lines of Wadi Deif camp in southern Idlib province, Sept. 18, 2014. Reuters/Khalil Ashawi

For more than three years, the Obama administration has tried in vain to engineer the downfall of Syrian President Bashar Assad without leaving the country in the hands of extremist Islamists. It has trained and armed so-called moderate rebel groups whose aims are more palatable than those of the jihadists who have captured large swaths of the country.

But now, by the reckoning of experts and members of Congress from both parties, that strategy appears in tatters. The moderates the United States bet on as the means of pressuring Assad have been routed by an offshoot of al Qaeda and the Islamic State group, a brutal entity also known as ISIS or ISIL that is associated with videotaped beheadings of its captives. And a new strategy based on training rebel groups in the south of the country -- rather than in the north where the campaign began -- has yet to be implemented.

"This may be a case of too little too late,” U.S. Rep. Ileana Ros-Lehtinen, R-Fla., said, speaking on Wednesday as chair of the House Subcommittee on the Middle East and North Africa, a group within the House Committee on Foreign Affairs.

"Airstrikes won't end the conflict and neither will boots on the ground," said Rep. Ted Deutch, D-Fla., adding that the U.S. should find a new way to ramp up support for the moderate opposition in Syria. But so weak and ineffective are the moderates who have operated under the banner of the Free Syrian Army that the Pentagon confirmed it is not working with the biggest groups that first received American arms, even as it prepares to launch a new program to train and equip rebels challenging Assad.

At the subcommittee hearing Wednesday, a panel of experts from major American research institutions -- some traditionally hawkish and others generally intent on a brokered peace -- all concurred on one point for the members of Congress who had convened: The U.S. has largely failed in its effort to arm and train a moderate opposition in Syria.

The U.S.-led strategy of airstrikes against the Islamic State in Syria “has actually hurt the moderate opposition," declared Robert S. Ford, a former Obama administration ambassador to Syria. He said the American airstrikes in Syria hit elements of the al Qaeda-affiliated Jabhat al-Nusra in the northwestern part of the country, which caused them to retaliate against the moderate rebels, who were largely unprepared to deal with such attacks and fled.

"We didn't warn the moderate fighters about our strategy and what it could encompass, so they were surprised and unprepared for the air attacks and the Nusra Front response," said Ford. "We should have explained our strategy to Syrian rebels. If it continues like this, there isn’t going to be a moderate opposition in northern Syria."

Rebels with the Free Syrian Army told the International Business Times that many fighters among the moderates have defected to other groups that are better equipped and in better position to seize territory -- not least, to Jabhat al-Nusra. "As we struggled to find who in the Syrian opposition to work with, some in the Gulf were funding extremist elements that had gained popular support simply because they were the best organized on and off the battlefield," said Deutch.

Some prominent observers now say the very notion of arming moderates has been exposed as bankrupt. “They are not a viable fighting force,” Leslie Gelb, an assistant secretary of state in the Carter administration and now a fellow at the Council on Foreign Relations, told IBTimes. “They couldn’t win no matter how many arms we gave them. That has been the story war after war, I don’t know why we have to learn this one lesson administration after administration. We learned this in Iraq.”

Others assert that the Obama administration now confronts an overdue reckoning with a discomfiting reality: It could soon be forced to accept the continued rule of its sworn enemy Assad -- a tyrant who unleashed chemical weapons on civilians -- or otherwise risk the victory of the Islamic State group, whose tactics have been denounced as extremist by none other than al Qaeda.

The administration has said publicly that it currently has a strict “ISIS first” strategy in Syria, meaning all other imperatives take a backseat to eradicating the jihadist force. “In Syria, our actions against ISIL are focused,” Defense Secretary Chuck Hagel said in a House hearing last week. "Our military aims in Syria are limited to isolating and destroying ISIL’s safe havens.”

Deputy National Security Adviser Antony Blinken has said the emerging threat of ISIS in Syria could actually help end the civil war in the country: The Syrian regime’s allies, including Russia and Iran, share a “profound interest in avoiding the emergence of an extremist Syria, a haven for extremist groups,” he said in July at a conference co-hosted by Foreign Policy and the Policy Planning Staff of the State Department. He added that the U.S. also wants ISIS gone, which points to a possible “convergence of interests.”

But other senior officials in Congress insist that the U.S. can still build up the moderate opposition if it implements better strategy. House Foreign Affairs Committee Chairman Rep. Ed Royce, R-Calif., said during a hearing in September that Assad’s “strategy is to present the world with a choice between accepting the regime and the ISIL extremists."

"Friends, we do not have to play his game," Royce said, rejecting the notion that the only alternative to the Islamic State is the continued rule of Assad. Former ambassador Ford said in the hearing that in recent months, Syrians who previously supported the regime have started to complain about Assad and the war by publicly demonstrating in the streets.

"If there is a way to reach out to those people ... and say look, it doesn't have to be a choice between Assad and jihadi crazies in Syria, there is a third way, then I can imagine moving forward along the lines [of a political solution]," Ford said. "But in order to do that you have to have a little more pressure on the regime. We need more pressure on the ground."

Sen. John McCain, R.-Ariz., said during an Armed Services Committee hearing recently that the U.S. would not gain followers among the moderate opposition if the weapons it provided them could only be used to fight ISIS. But the rebels have so far failed to demonstrate an ability to simultaneously fight both ISIS and Assad. Instead, they have been losing on both fronts. Islamist groups such as Jabhat al-Nusra and the Islamic State are making more gains in regime territory, especially in the northern part of the country.

A source affiliated with the Free Syrian Army, who spoke on condition of anonymity, citing threats to his safety, said the rebels “are a bit lost on what they are doing,” adding that they “have no strategy.” Some rebels fighting for the largest opposition battalions in the North are “becoming more sympathetic to ISIS,” he added.

The Obama administration is now considering refocusing its attention on the southern part of the country by increasing the number of rebels armed and trained by the U.S., according to Mohammed Ghanem, a senior political adviser senior political adviser in Washington, D.C., at the Syrian American Council, a grassroots organization based in Chicago. Those rebels could be trained under a new train-and-equip program run by the Department of Defense.

The previous arms program in Syria, the one that supported rebel groups such as Harakat Hazm, the main moderate opposition group receiving U.S. arms in the north, was largely funded and managed by the CIA. However, several members of the Free Syrian Army told IBTimes that the Department of Defense was also involved in that program since the beginning, particularly in the vetting process.

Despite the claims by leaders in the Free Syrian Army, the Department of Defense said in an email this week that it had not begun its train-and-equip program in Syria and that in the past it had only provided nonlethal support to the opposition. The CIA declined to comment.

“A lot of what we have been giving [the rebels] has been off the books,” Gelb said. “It is all super secret.”

The U.S. strategy in Syria has fundamentally shifted in recent months to focus on defeating ISIS, but that strategy should no longer include relying heavily on the moderate opposition, Gelb said. “They don’t have the capability,” he said. “It was a dream on the administration’s part. We haven’t given [the rebels] enough time, and we have asked them to do more than they can.”

Ghanem said the opposition was never given the time or resources to make an impact. “I can still remember meeting administration officials in 2012 when the moderate Free Syrian Army was the dominant anti-Assad group. I tried to warn them that if the U.S. continued to let Assad crack down with impunity, it would create a vacuum that radicals would fill,” he said. “The president was never interested in giving democracy in Syria a chance. I am sure he will think up another excuse for inaction.”

Moving forward, Gelb said, the U.S. should work with Assad -- an option that the opposition in Syria fears would ruin any prospect of them gaining power in the country. “I think we need to have some sort of working arrangement with Assad to have him focus his military efforts against ISIS and not against the rebels,” Gelb said, adding that the U.S. should “gradually arm the rebels and put them in a position down the line to prove themselves.”