President Obama said this week that NATO's plan to turn the lead role in the fight in Afghanistan over to that country's own forces by next summer is "irreversible." That's what Americans, Britons and other NATO allies want to hear. The alliance has been in the embattled nation for too long and it's past time to come home.
If the Chicago summit makes the reality of the withdrawal crystal clear to everyone, everywhere, so much the better.
The departure of the alliance is not without risk, of course. The ability of the Afghan army and police forces to hold the nation together and protect it from the Taliban insurgency is dubious. Clearly, however, it also is doubtful that the United States and its allies could improve that situation by extending the stay of their forces there. One nation cannot forcibly change the culture and politics of another nation in even a century, let alone a decade or two. That certainly has been the history in Afghanistan, where a succession of empires has tried just that and failed.