(DoD photo by Mass Communication Specialist 1st Class Chad J. McNeeley, U.S. Navy)

President Obama’s request to Congress for authority to use military force against the Islamic State explains his view of why to fight this war. But it doesn’t really tell us how.

Obama has asked to be liberated and constrained at the same time. He wants no geographical boundaries placed on his ability to go after the Islamic State and “associated persons or forces.” But he also asks that Congress rule out “enduring offensive ground combat operations” and wants the war authority to expire after three years.

This is walking an awfully fine line. One has to wonder whether the president is trying to satisfy both hawks and doves in Congress — or displaying his own ambivalence about using military force in a situation where, he has said, there is “no American military solution.”

In the official letter he sent to Congress on Wednesday, Obama lays out a maximalist case for going to war. “The so-called Islamic State of Iraq and the Levant (ISIL) poses a threat to the people and stability of Iraq, Syria and the broader Middle East, and to U.S. national security,” Obama writes. He notes the group’s brutal killings of U.S. citizens and adds: “If left unchecked, ISIL will pose a threat beyond the Middle East, including to the United States homeland.”

For the record, I’m aware of no evidence that the Islamic State has al-Qaeda-style plans to attack the United States. But the group clearly has the ability to inspire violent sympathizers around the world — as was apparently the case with at least one of the perpetrators of the Paris terror attacks.

It is also clear that the consolidation of a sprawling “Jihadistan,” occupying a vast territory carved out of Iraq and Syria, would be enormously destabilizing. Such ungoverned spaces are petri dishes for terrorism, and even if the Islamic State’s leaders do not dream of staging attacks on U.S. soil, they could — as did the Taliban — provide a haven for others who do.

But how urgent is the threat? This is a question Obama seems to want to defer.

I’m not sure the prohibition against “enduring” ground combat operations is terribly meaningful, given that Obama has less than two years remaining in office. He obviously has no plans for any kind of massive invasion or occupation, but the measure he sent to Congress doesn’t technically rule anything out.

He said Wednesday that there are now 2,600 U.S. troops in Iraq, largely serving “on bases,” with the mission of training Iraqi forces to fight their own war. It is possible to envision that Kurdish troops, aided by U.S. special forces on the ground and supported by U.S. airstrikes, will be able to recapture significantly more territory from the Islamic State in the north.

But that would still leave the Islamic State in control of the Sunni heartland, and the shambolic Iraqi army is in no condition to do anything about that fact. Hopes of another Anbar Awakening in which Sunni tribal leaders help drive out the terrorists depend on a political agreement in Baghdad that remains elusive, if not unimaginable.

Still, for the sake of argument, imagine that Obama’s strategy somehow managed to drive the Islamic State militants out of Iraq. That would still leave them in control of much of Syria, where U.S. policy is quite different.

Concentrated U.S. and allied airstrikes managed to keep the militants from capturing the strategic town of Kobane, near the Turkish border, but this was primarily a symbolic victory. The Islamic State has actually been expanding its territory in Syria. Dictator Bashar al-Assad, meanwhile, has taken advantage of the airstrikes against the Islamic State to rout the “moderate” Syrian rebels — the ones Obama says he wants to arm, train and support.

Under the best-case scenario, it seems to me, the Islamic State will still control much, if not most, of Syria when Obama’s successor takes office. Under what I consider a more realistic scenario, the militants will also control at least part of the Sunni region of Iraq. Perhaps the Islamic State will be “degraded,” as Obama promises — but not “destroyed,” as he also vows.

Obama’s aim seems to be to leave his successor a somewhat smaller and less threatening problem. Maybe that’s all that can be done. But wars, once started, develop their own logic and momentum. The first of many questions Congress should ask is why Obama wants to pursue a military solution when he says none exists.

Eugene Robinson’s e-mail address is eugenerobinson(at)washpost.com.

© 2015, Washington Post Writers Group

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