Officially, the Pentagon is sticking to its policy of battling ISIS’ advance in Iraq without the aid of Iranian-backed militias. Unofficially, there are signs of a policy shift that could mean closer cooperation with the militias fighting the terrorist group.

"The militias have a part to play in this. As long as they are controlled by the central Iraqi government, then they will participate," Pentagon spokesman Army Col. Steve Warren told reporters on Monday. That’s a long way from the line drawn by top U.S. Defense officials less than two months ago when militia coordination was emphatically ruled out.

The reason for the change is the fall of Ramadi, a Sunni city in Iraq’s Western Anbar province and ISIS’ most significant gain since taking Mosul last June. Ramadi’s beleaguered security forces proved to be no match for the ISIS assault launched last week. The ranks were already ill equipped, rotted by corruption, and exhausted from battling ISIS for more than a year—when faced with the latest onslaught, many fighters appear to have fled.

In the wake of this defeat, Iraq’s political consensus has turned to the militias and volunteer groups, known as the Hashd al-Shaabi, as the country’s best hope.

Nominally, the Hashd structure was created to incorporate both Sunni and Shia volunteers into the military. In practice, it is a predominantly Shia sectarian force, weighted toward larger groups like Asaib Ahl al-Haq (AAH) and the Badr Organization that are backed by Iran’s military Quds force, which the U.S. has cited as reasons to refuse cooperation.

After the loss of Ramadi some Sunni leaders from the area, including Anbar’s provincial council, have called for support from the Hashd to help them fight ISIS. Currently, there are a reported 3,000 Shia militiamen staged just east of Ramadi at the Habbaniyah military base, prepared to launch a counteroffensive. Dr. Hisham al-Hashimi, an adviser to the Iraqi government who is widely viewed as Iraq’s pre-eminent ISIS analyst, tweeted recently that the number will increase to 6,000 before a future operation in Ramadi begins. According to Hashimi’s projections, the militias will then outnumber the 1,500 members of the uniformed security forces participating in the operation by three-to-one. According to al-Hashimi, the Hashd forces are “the only antidote to ISIS.”

Still in its early stages, Baghdad’s plan to counter ISIS’ gains in Ramadi appears to follow the model applied in the recent operation to retake Tikrit, another Sunni city that had been under ISIS’ control.

“Yes, the militias were critical in Tikrit,” a senior defense official told The Beast’s Nancy Youssef shortly after ISIS was pushed out of the city. “But that does mean we could not have operations without them,” he said. As Youssef reported, the defense officials’ assessment was that “working around the militias is ‘not insurmountable’.”

In Tikrit, the heavy reliance on Iranian planning and sectarian militias—by some accounts Iraq’s Prime Minister Abadi only learned of the operation after the planning was done without him—caused the U.S. to the withhold air support that had been crucial in other operations against ISIS. It was only after the militia-led offensive stalled weeks into the fighting that Baghdad requested American air support, which the U.S. provided on the conditions that the militias withdraw from the fighting.

"I will not, and I hope we never, coordinate or cooperate with Shia militias," General Lloyd Austin, the head of Central Command, told Congress in March, the day after the U.S. began launching airstrikes in Tikrit.

Compare that to the position taken on Monday by Pentagon spokesman Steve Warren about the militia’s “part to play in this.” On that same day, Iran’s Defense minister Hossein Dehghan arrived in Baghdad to meet with his Iraqi counterpart, General Khaled al-Obeidi. Those meetings concluded with what an Iranian news agency closely aligned with Tehran’s government called, “agreements on widening defense and security cooperation.”

Not all of Iraq’s militias are aligned with Iran, but it is the militias with the closest ties to Iran like Asaib Ahl al-Haq that are taking on the largest role in the planned operations for Anbar and thus, have the most political leverage.

Of the militia fighters who have deployed around Ramadi after the city fell, “I think about half of them are from Asaib ahl Haq,” said ++Joel Wing++, a researcher and analyst of Iraqi politics. “[Asaib ahl Haq] said they sent 1,500 fighters, so its 3,000 fighters and at least half of them are from AAH.”

Of course, it’s too early to say how the militia groups will operate in Anbar. Whether they stay under Baghdad’s control or, as in Tikrit, consult with Tehran may determine the level of cooperation the U.S. is willing to provide. Regardless, that the Pentagon has come to see some level of support for the groups as necessary is a marked shift.