With Gen. David Petraeus testifying to a congressional committee behind closed doors today about Libya in his former role as CIA director, his flawed legacy in Afghanistan has become obscured amid the waves of scandal lapping around him.

In Afghanistan, Petraeus oversaw the militarization of President Obama’s foreign policy, the “surge” of U.S. troops aimed at preparing for a phased handover to a professional force of Afghan troops and police, using his Iraq counterinsurgency policy as a model. The policy of using the military for nation-building is now in tatters, with the powerful U.S. military demoralized by the “green on blue” attacks by Afghans against their mentors, the Afghans’ screening and training called into question on a daily basis. Sixty-one coalition soldiers have been killed by members of the Afghan National Army or police this year.

The London Times today carried a front-page article headlined: “Afghanistan not worth life of one more soldier.” It’s the view of an influential former leader of the Lib Dems, Lord Ashdown (whose party is now in coalition government with the Conservatives), as America’s closest ally prepares to pull out remaining forces by the end of 2014. He is urging British Prime Minister David Cameron to pull out the British troops as quickly as “decently” possible.

Notably, he says, “It is now crystal clear that we have lost in Afghanistan. We have succeeded in only one thing: albeit the big thing we went to war for — driving out al Qaeda. In almost all the other tasks we set ourselves, especially the establishment of a sustainable state, we have failed.”

As commander of the U.S. and NATO forces from June 2010 to July 2011, Petraeus carries his share of responsibility for that failure. As head of the CIA, he intensified the drone attacks on the tribal areas of Pakistan, which have done so much to nurture anti-Americanism and extremism in that troubled region by their unintended killing of civilians.

What has America to show for 11 years of war in Afghanistan? Sadly, a Groundhog Day vision with the Taliban poised to return to power. I would echo Ashdown and say it’s time to pull out American troops too, as quickly as decently possible.