ISLAMABAD -- For the last decade, the United States and Afghanistan have viewed Pakistan as part of the problem as they worked to subdue the Afghan insurgency. Yet suddenly the three countries are working together for an Afghan peace, with Pakistan handling one of the trickiest aspects of the effort: bringing the Taliban to the talks.

From villain, Pakistan has emerged as the key to working out a deal, an amazing transformation for a country that was long seen as the Taliban’s main foreign backer when they were in power in Afghanistan, and whose territory, willingly or unwillingly, provided a haven when U.S. and NATO drove the Taliban from power in 2001.

Driving the new collaborative spirit after years of acrimony, diplomats say, was one thing: fear that chaos will follow the NATO withdrawal from Afghanistan in 2014. .Such anarchy could cost thousands more lives in Afghanistan, make a mockery of the U.S.-led coalition’s claims of success, threaten the security of Pakistan and allow international terrorists, including al Qaida, to find sanctuary there again. Other countries also are involved heavily in the diplomatic push for peace negotiations, especially Turkey and the United Kingdom. Last month, Pakistan took the first step in trying to build confidence, freeing 18 low-ranking Taliban prisoners last month whose release the extremists had sought.

Pakistan had been ready to cooperate a year ago, said diplomats who, like other officials quoted here, spoke only on the condition of anonymity because of the sensitivity of the issue. But that was impossible after relations between Washington and Islamabad nearly broke down in the wake of a “friendly fire” incident in November last year in which American aircraft killed 24 Pakistani soldiers manning a border post. Ties between Pakistan and the United States were repaired only this summer.

Pakistan has called for a political settlement with the Taliban for years, an arrangement that would give them a share of power in Afghanistan. But the Afghan government until now hasn’t been willing to trust Pakistan, suspecting that the Pakistanis wanted a return of the Taliban government, and the United States has pursued a policy that saw negotiations as something that could come only after decisive gains on the battlefield.

But that attitude has changed as it’s become clear that the surge of troops President Barack Obama ordered to Afghanistan in 2009 failed to change the course of the war. With thousands of troops having returned home and tens of thousands more to follow soon, a cease-fire now wouldn’t be so painful for the United States.

The new cooperative effort, which McClatchy revealed last weekend, envisions a cease-fire in the second half of next year. It also contemplates the Taliban holding public posts that would essentially hand them control of parts of Afghanistan.

For Pakistan, a peace accord is vital because it has a ferocious extremism problem of its own, including a Pakistani version of the Taliban. Islamabad thinks that once the Afghan Taliban and its allied Haqqani network are politically accommodated in Afghanistan, they’ll abandon Pakistani territory. That would allow Pakistan to move against its own militants.

The two stripes of militants often share the same geographical space along Pakistan’s border with Afghanistan, making that region an ungovernable threat to the whole of Pakistan.