Yet the president chose not to exploit this win. The White House issued a five-paragraph statement. Much of last week was consumed with the president's feud over his phone call to the mother of one of the soldiers killed in Niger.
How to explain the subdued reaction? (After all, this White House is desperate for policy wins.)
It's the geopolitical equivalent of "Mo Money Mo Problems." Success brings new challenges. In this case, the eclipse of the Islamic State reopens old rifts in the Middle East that were paused to defeat a universally loathed enemy. Even the U.S. and Iran could cooperate (tacitly) against an outfit that operated sex-slave markets and attempted genocide.
Now all of this fair-weather esprit de corps is gone. One glaring example is in northern Iraq, where the Iraqi Security Forces advanced on Kurdish Peshmerga positions in the last week following their recapture of Kirkuk, the oil-rich city Kurdish forces protected from the Islamic State in 2014. But there are small examples as well. In Raqqa there are now reports the Kurdish YPG militia have started taking down Syrian revolutionary flags favored by Arab members of the opposition forces that liberated the city, according to Jennifer Cafarella, senior analyst with the Institute for the Study of War.
This says nothing of the new tensions between the U.S. and Iran in Iraq. This week Secretary of State Rex Tillerson earned a rare public rebuke from the Iraqi prime minister's office after he called on Iranian-supported militias fighting the Islamic State to return home now that the fight is coming to a close. Only two years ago, the U.S. was providing air support for ground offensives led by these militias in that fight.
Cafarella told me that one of the problems with the U.S. strategy against the Islamic State is that it was almost purely a military one, without the much-needed political component necessary for winning the peace. "What we have not addressed are larger institutional and societal challenges that gave rise to ISIS to begin with, and are now fueling the cascading crisis in Iraqi Kurdistan," she said. "The very best example of that is that we have ignored and overlooked Iran's penetration into the Iraqi Ministry of Interior and the Ministry of Defense."
In many ways this is an old story. Iran's penetration into these institutions vexed George W. Bush before he decided to "surge" troops into Iraq and pursue a counterinsurgency under the leadership of Gen. David Petraeus. One of the White House staffers who argued for that strategy was Brett McGurk, the American diplomat who went on to forge the coalition against the Islamic State. At the time, the U.S. pursued both Sunni and Shiite terrorists in Iraq, targeting any groups that threatened the elected government. Much of that strategy relied on a close partnership between Bush and the Iraqi prime minister at the time, Nouri al-Maliki.
Eventually Maliki, a Shiite Arab, succumbed to sectarianism. Under Obama, he pursued a ruthless campaign against Sunni groups in the west of the country, laying the ground work for the rise of the Islamic State. Maliki reasoned that if Obama was intent to leave, he best make his peace with Iran. After the Islamic State began to take territory and went on a rampage in 2014, Obama abandoned his non-interventionism. He instructed McGurk to find an alternative that summer. That alternative became Haider al-Abadi, who ascended to be prime minister that September. The Iranians supported Maliki in that power struggle and eventually lost.
Today Abadi is at a crossroads again. His security forces have pressed ahead into Kurdish areas over the objections of the U.S. government - though a cease-fire was said to be reached on Friday. The situation threatens to pit two Iraqi forces, both supported and armed by the U.S. government, against one another, even though only a month ago they were cooperating against the Islamic State.
It follows a certain depressing logic. Without an enemy to unite them, America's allies in the Middle East return to fighting one another.