The best recent analysis of the military choices America faces is by Columbia's Dick Betts [a longtime friend] in his Foreign Affairs article, "Pick Your Battles," in the November-December 2014 issue. Among his recommendations:
First, the United States should fight wars less frequently but more decisively.... Second, the country should avoid fighting in places where victory depends on controlling the politics of chaotic countries, since local politicians will rarely do what Americans want when that differs from their own aims. And third, Washington should give priority to first-order challenges, focusing its military planning on fighting wars with great powers and focusing its diplomacy on preventing them.That second point is especially relevant in figuring what to do about Syria and ISIL. A typical military-centered strategy by Gary Anderson in the Small Wars Journal makes this error. It is superficially encouraging and persuasive as it makes the case for a large-scale western military intervention -- massive boots on the ground that few armchair strategists are willing to recommend.
The problem comes in the second pillar of his strategy:
Phase II (Iraqi) stabilization. This should probably be simultaneous with the third Phase in Syria, but it should not require continued long-term US military involvement in Iraq. This should be primarily a diplomatic-political effort. The Iraqis need to re-forge a constitution that gives more local say and amore even distribution of oil and mineral assets to the Kurds and Sunnis. Whether this means more federalism or a confederation is less important than eliminating the grievances that allowed for the rise of the Islamic State in Iraq.Trouble is, that's what we've been trying in Afghanistan and Iraq for a dozen years, buying time for diplomacy and domestic politics with U.S. and allied forces. We bought the time, but we never could dictate the necessary local reconciliation or stabilization. So however brilliant the military activities may be, they are always insufficient.