Aha. Below I wondered whether all those weapons found in Fallujah were really significant or merely a drop in the bucket. Juan Cole puts up some hard numbers to argue for the "drop in the bucket" thesis. Indeed, if you look at this slide in particular from the 1MEF slideshow on Fallujah, you'll notice that they've recovered a mere16 pounds worth of C4, only 280 RPGs, only 10 surface-to-air missiles, etc. I'm honestly no expert, but that doesn't sound like a whole lot. Intuitively, too, you'd think that if the insurgents in Fallujah had all this time to prepare for a U.S. strike, they'd think of something a bit more crafty than simply slipping out and leaving the bulk of their armory behind.

Speaking of which, in that same post I suggested that, given enough weaponry, the Sunnis would have no trouble taking over Iraq again if the U.S. left. (I'm assuming that they would aim for central and south Iraq, and mostly leave the Kurds alone.) Well I just read Noah Feldman's excellent What We Owe Iraq, and he argues that the Sunnis could do no such thing—they held Iraq in the past only because Britain outfitted them with the right sort of state power apparatus to do so. Fair enough, but is it really so implausible that a well-armed (and well-funded) minority could take over a largely disorganized and fractured state? Isn't this the same situation the Taliban faced in the early 1990s?

Besides the U.S., the only thing that could stop Sunni domination, I think, would be either a fierce challenge from the Kurdish peshmurga, or intervention from Iran. Or—even more likely—the insurgency would fracture, between the tribal nationalists, Baathists, and Islamists. At any rate, my main point is that, given enough popular support, the Sunni "insurgency" could in theory wage a capable conventional war and do a lot of damage.