For a time, both American and Iraqi officials denied reports that indicated Iranian military forces were operating openly in Iraq and aiding in that country’s fight against the Islamic State. When the signs of Iranian military operations in Iraq became overwhelming and undeniable, both Iraqi and American officials acknowledged Iranian military involvement in Iraq. American commanders and administration officials stressed, however, that there was no cooperation with Iranian military commanders. In fact, administration sources insisted that the United States routinely went out of its way to avoid the appearance of collusion with Iranian operatives on the ground in Iraq. Still, enterprising journalists revealed on several occasions that American involvement in the fight against ISIS had resulted in aiding Iranian military operations, albeit possibly inadvertently. That covert support for offensive operations in Iraq led by Iran is apparently about to become overt.

The operation to retake the Iraqi city of Tikrit from ISIS, led by Iran and Iraqi Security Forces and aided by Shiite militias loyal to Tehran, has stalled. On Tuesday, The Wall Street Journal revealed that American aerial intelligence units had begun to provide Iraqi forces and Iran-backed militias with support.

“Military officials said they aren’t working directly with Iran,” the report read. “But the intelligence will be used to help some 20,000 Iranian-backed Shiite militia fighters who make up the bulk of the force that has been struggling for weeks to retake the strategic city.”

The Pentagon said Tuesday that the campaign had stalled amid tough fighting by hundreds of Islamic State fighters still holding most of Tikrit. At the request of the Iraqi government, the U.S. military began providing aerial video of the city, said an official with the American-led coalition helping Iraq fight Islamic State.

The U.S. involvement could pave the way for American airstrikes in Tikrit, hometown of onetime dictator Saddam Hussein.

The way having been thoroughly paved, apparently, The Daily Beast discovered on Wednesday that American air support for Iranian-backed combat operations on the ground was imminent.

An American air strike campaign in Tikrit would mark an important shift in the ISIS war. Iraqi officials did not engage their American counterparts before they launched the offensive on Tikrit March 1, with Iranian generals and tanks by their side. And the American military has long insisted that it wouldn’t coordinate too closely with the Iranians, even as both forces fight a common enemy in Iraq: ISIS.

The Tikrit campaign was launched with a patchwork force of 20,000 Shiite militiamen, 3,000 Iraqi troops, and a bevy of Iranian troops, tanks, weapons and missile strikes. And in the early days of the campaign, Gen. Qassem Suleiman, leader of the Iranian Quds force, was on the ground in Tikrit.
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U.S. officials told The Daily Beast that the heaviest resistance to expanding the American involvement to air strikes will not be from the Obama administration—which has long shrugged off the idea of cooperating militarily with Iran—but from some Shiite militia leaders who have said they can reclaim the city without American help.

“The Shiite militia leaders have been saying we don’t need American air strikes so they have been pushing back on this idea. So there is going to be an internally debate within the Iraqi state,” the adviser said.

Shortly after this report was published, the airstrikes in support of ground forces reportedly began.

WASHINGTON (AP) — US airstrikes underway in stalled Iraqi battle to retake Tikrit from Islamic State group.

— Dion Nissenbaum (@DionNissenbaum) March 25, 2015

As The Daily Beast report indicates, Iranian military cooperation with the United States is as vexing a political problem for officials in Tehran as it is in Washington. If prestige is on the line, that’s one thing, but there may also be some American tactical considerations that defense officials believe could be advanced by conducting airstrikes in support of Iranian-led anti-ISIS missions.

“If this leads to the Iranians forced to concede defeat, that would be a satisfactory outcome,” said an unnamed defense official in The Daily Beast’s report.

Huh? That’s a strange statement. Precisely how would aiding the success of an Iranian-backed advance into Tikrit resulting in that city’s fall to Iraqi and Shiite forces precipitate Iranian contrition? It’s rare that major tactical victories produce an overwhelming sense of regret in the victor.

That quote sounds like a bit of wishful thinking on the part of this unnamed defense official, and perhaps it helps for those coming to terms with American-Iranian battlefield cooperation in Iraq. But that cooperation is coming, and it is forcing America’s traditional Sunni allies in Cairo and Riyadh to rethink their approaches to domestic and regional security. Whether or not some think America’s shifting alliances in the region are necessary, this change in U.S. grand strategy is self-evidently destabilizing.