If 150,000 U.S. troops could not stabilize Iraq in the absence of an inclusive and competent government, the limited measures on offer now simply will not suffice. And we should know by now that any Western military intervention with overtly political, rather than clearly humanitarian, objectives runs a real risk of inflaming sectarian sentiment.
It's worth remembering these days -- as President Obama declares that air power will be the primary and perhaps only U.S. effort against ISIS in Iraq and Syria -- that the impressive Pentagon videos of missile warheads exploding in the crosshairs obscure the difficulty that air power has in achieving positive, lasting effects on the ground. And that the effects of air campaigns diminish over time -- as the Germans discovered when their intense bombing of London in 1940 failed to break Britain's will. Shock and awe are short-lived.