The announcement by the US defense secretary that US troops will no longer take a lead role in Afghan combat before the end of 2013 stunned the Afghan government in Kabul but will probably please voters in the US. It largely cuts the ground out from under the feet of negotiators; the Taliban cannot have much incentive to negotiate vital interests with a power so obviously bent on escape.The move probably reflects several ideas that seem uppermost in Washington’s mind. First, that the war cannot be won at a price the US would be well-advised to pay. The Taliban cannot be destroyed on the battlefield as long as it has ISI backing and Washington cannot force the Taliban’s friends in Islamabad to stop supporting the group. Second, that the Kabul government is a hopeless mess and will only stir itself when faced with the loss of its military support by the west — and maybe not even then. Third, that the US has had enough success in breaking up Al Qaeda’s operations, and through drone strikes and other means, of attacking Al Qaeda’s remaining supporters in the region that protecting the homeland from Al Qaeda no longer requires a US war role in Afghanistan.It will be hard for the US military to fight this assessment, even though many remain more optimistic than the White House. Public opinion has long been cool toward the Afghan war, and the death of bin Laden (rather than the construction of a stable and at least quasi-democratic Afghanistan) was the primary goal in the region that most Americans wanted achieved. With bin Laden gone and Al Qaeda in disarray, it is hard to make a strong political case for further US involvement in the war.Washington probably also hopes that others in the region — India, Russia, Iran, China — who do not want the Taliban back in Kabul for various reasons will concentrate on helping the current Kabul government develop a survival strategy. In any case, after concluding that there are no longer any great national interests tying the US to the future of Afghanistan, the Obama administration is moving to liquidate the war.