America’s challenge in confronting ISIS (a.k.a. “the Islamic State”) is, not simply to “degrade and ultimately destroy” the group, but to do so without indirectly bolstering the Iranian dictatorship and its various clients and proxies. After all, ISIS is one enemy that the United States, Iran, Syria, Hezbollah, and Iraq’s Shiite militias all have in common. That’s a deeply awkward, uncomfortable strategic reality, but it’s one that cannot be ignored.

Adam Garfinkle of The American Interest recently published a sharp analysis that addressed both (a) Iran’s role in the emergence of ISIS and (b) the broader Iranian threat to U.S. interests in the region:

“ISIS did not just fall from the sky one day. As I have explained before in this space, Iranian hegemonic exertions, via support for the murderous Assad regime in Damascus, via Hizballah, and via Muqtada al-Sadr’s Jaish al-Mahdi in Iraq and its latter-day incarnations (Asaib Ahl al-Haq, notably), and other machinations as well, to include the political subversion of Lebanon, have raised an existential threat to the Sunni Arab regimes and have radicalized heretofore mostly latent sectarian cleavages in the region. When the feeble Sunni Arab states proved feckless in responding, the radicalization process, with mischievous help from countries like Qatar as well as Turkey, created the monster that is ISIS. The point? It is not possible to extirpate ISIS unless we also address its source: Iranian power projection through Arab Shi’a militias (which, by the way, extends all the way to the Houtis in Yemen).

“That is why, if the United States attacks ISIS in Syria, it must also attack Assad regime assets and, for good measure, those of Hizballah as well. A good start, as others have recommended, is to crater the airfields where weapons transports arrive from Iran and Russia. Otherwise, the moderate Sunnis we hope to enlist as allies against ISIS will conclude that we have secretly sided with Tehran. And a nuclear deal that can be interpreted as a win for Iran will mightily reinforce that perception.”

Garfinkle also believes that “there is no more Iraq as a state or Syria as a state,” which raises major questions about what would come after the elimination of ISIS:

“The future of the Levant, or at least the parts that used to make up Iraq, Syria, and Lebanon, is up for grabs. So is the land on which Kurds live in four countries. That future depends on a series of interlocking contingent decisions not yet made, so no one can readily predict it. But generically speaking, there are only three possibilities.

“One is that borders will be rearranged and newly configured states and statelets will emerge. Syria could be divided into a rump Latakian-Alawi state running along the Mediterranean from the Turkish border south to the Lebanese border, and encompassing the great Damascus area, and a Sunni state stretching from Aleppo eastward into the desert and south to Dera’a. Iraq could be split into a Shi’a state in the south, a Kurdish state in the north/northeast, and a Sunni tribal area in between — like the current status quo somehow formalized. Lebanon might or might not be absorbed in part into a Syrian fragment.

“A second generic possibility is that the area will be divided, with some Shi’a and Kurdish and Alawi statelets and rumps congealing but with the vast swaths of the Sunni tribal areas being absorbed into Saudi Arabia and Jordan. There is a possibility, too, that the Shi’a areas of Iraq might be absorbed into Iran, but this is unlikely because Persian and Arab blood is thicker than Shi’a water.

“A third possibility is that urban areas will have something like normal government, but that vast stretches of the region will return to their tribal status quo ante, reminiscent of the 14th-16th century period between the rescission of the Mongol armies and the arrival of the Ottomans.

“The chance that a single imperium could cover and control the entire space, as in the days of Assyria, Babylon, and the Persian Achaemenids or Sassanids, seems very far-fetched. Too bad, in a way, because the national security challenges for the United States of this fourth possibility would probably be a lot less acute than those of any of the other three.

“But that is where the region is heading, to one of those three highly uncertain situations. If we had a strategy really worth the name, that is what we would be thinking about now — because the destruction of ISIS and the fate of Bashir al-Assad pale beside the real decision points to come. And they’ll be coming faster than most people seem to realize.”