Stories on President Obama’s strategy-for-the-Islamic-State speech this evening have made it plain that the military approach is going to be a combination of U.S. airpower and various Iraqi and Syrian proxies on the ground. “Obama’s ISIL Strategy to Emphasize Coalition Effort,” headlines RealClearPolitics.

Since the administration repeatedly has drawn a “red line” on U.S. “boots on the ground,” this comes as no surprise.  But it will come at a cost, measured primarily in time but also perhaps in terms of mission failure.  There are limits to what American airpower can achieve, particularly when applied in penny-packets and under operational constraints.  And there are also lots of limits to what the on-the-ground members of any coalition can accomplish.