Retraction is always hard
This essay is an impressive piece of political recanting. One, because I totally agree with where the author ends up, and two, because such public admissions of error are so rare. Contrast with The Economist, which still claims that the decision to invade Iraq was right given the evidence available to the concerned governments (even if the information was bogus, and quite possibly concocted to please the people asking for it), and that invading Iraq went so wrong because of poor execution.
If they’d stuck to Afghanistan, where it does appear as if NATO intervention is improving things, how much more kindly we’d judge them.