Over at the New Republic's now-defunct &c. blog, Spencer Ackerman observes that the U.S. is now even further away from training the new security force in Iraq than it used to be. The problem is that, while the training itself is going decently, the semi-independent Iraqi government now needs even more troops325,000 rather than its previous estimate of 275,000to counter an insurgency that continues to grow. (And in all likelihood there's still room for the insurgency to expand even further; see John Robb's figures.)
Although there's got to be an upper limit here, it's not too implausible to expect an endless spiral of this sort over the next few years: the U.S. can't get the new Iraqi army fully trained because the requirements keep moving upwards, which means that American troops stay for longer, helping to swell the insurgency even further, and meanwhile the predominantly Shiite-and-Kurdish army have just enough presence to antagonize Sunni Iraqis but not enough presence to maintain law and order and defeat the insurgency, so the requirements for the new Iraqi security forces go up yet again. One would hope this doesn't actually happen but it certainly seems to be the trend so far.