There's been a flood of news coverage of a major U.S offensive against the Taliban in southern Afghanistan. But a less-heralded operation that's just been made known could be more crucial in the long run. I refer to the recent capture of the Afghan Taliban's military chief — in Pakistan.

This event is a stunner, not just because a key Taliban leader was nabbed, but because it shows a new level of U.S.-Pakistani cooperation in fighting the militant group.

Mullah Abdul Ghani Baradar, second only to Afghan Taliban commander Mullah Mohammed Omar, was caught in a secret joint operation by Pakistani and American intelligence forces in Karachi. Such coordination was unthinkable a year ago.

Pakistani generals and intelligence chiefs have been reluctant in the past to aid U.S. efforts to crush the Afghan Taliban, whom they helped train in the 1990s. They saw their Taliban ties as a hedge against American failure in Afghanistan, in which case a Tali-ban government would be preferable to one influenced by India.

The Achilles' heel of President Obama's new Afghan strategy has been the safe havens the Afghan Taliban retained in Pakistan just over the border. U.S. officials said Pakistan's spy agency knew where Taliban leaders were hiding. So does the capture of Baradar signal that Pakistan's attitude has changed?

Not totally. But the change is significant enough to affect the entire fight against the Taliban — for the better.

To understand the shift, a little history is in order.

"What has changed is the situation in Pakistan," Gen. David Petraeus told me in an interview. He was referring to events in April 2009, when Pakistani Taliban leaders in the Swat valley broke a pact with the government and started advancing toward Islamabad. Swat was a vacation destination where many middle-class Pakistanis honeymooned; the violence there shifted public and media opinion.

"The entire country, the leaders, the people — all decided about 10 months ago that it was vital to take on the extremists in the Swat valley and environs and their allies," said Petraeus. "That is what has changed so dramatically."

The public's attitude was further swayed when suicide bombers began to kill scores of civilians, police, and military officers. "This is about Pakistanis confronting the most pressing existential threat they face," Petraeus said, "while keeping in mind that the traditional threat is always India."

Yet many questioned whether Pakistan's military would be willing to confront the Afghan Taliban, America's prime target, or would aim at only the militant groups it was fighting. Could the strategic interests of the two countries ever converge?

There were numerous signs of a gradual convergence, even before the Baradar arrest. Despite its domestic troubles, the government of President Asif Ali Zardari has always recognized the centrality of the jihadi threat to Pakistan. Adm. Mike Mullen, the chairman of the U.S.' Joint Chiefs, and Petraeus worked to build relationships with their Pakistani counterparts, as did Obama's team.

The new symbiosis could be seen in the intelligence-sharing behind an increased number of Predator strikes that successfully targeted not only our al-Qaida enemies but also jihadis on Pakistan's list.

And Pakistani attacks against its Taliban enemies in South Waziristan also squeezed U.S. targets elsewhere. A senior U.S. military official told me, "That has very much reduced the freedom of action of all of these groups, not just those aligned with Pakistani Taliban."

One of the most intriguing signs of convergence has come from Pakistan's army chief, Ashfaq Parvez Kayani. In a rare news conference, he said Pakistan doesn't seek a Talibanized Afghanistan. He offered Pakistani help in training the Afghan army and mediating with Taliban factions.

The Kabul government, which distrusts Pakistan's military and spy agencies, is deeply skeptical. But the arrest of Baradar may signal that Pakistan's security establishment is no longer wedded to the Afghan Taliban, but is pushing its leaders to break with al-Qaida, lay down arms, and come to the table.

The arrest of Baradar, if he's handled well, might persuade other top Taliban to stop fighting and start talking. Such talks, which Afghan President Hamid Karzai wants, won't happen without Pakistan's help.

The arrest may also indicate that U.S. and Pakistani policies toward Afghanistan are inching closer together in fits and starts, with the military campaigns of each side complementing the other and sometimes joining forces. In a period of bleak political news for Obama, that would be good news indeed.