The objectives of the war have become increasingly uncertain in a conflict where Taliban leaders say they do not feel the need to control territory, at least for now, or to defeat American and NATO forces — only to outlast them in a region that is, in any case, their home.

The Taliban’s tenacity, military officials and analysts say, reflects their cohesive leadership — successfully maintained since being driven from power in Afghanistan —, their ability to attract a continuous stream of recruits, and their advantage in having a haven across the border in Pakistan. While the Taliban enjoy such a sanctuary, they will be very hard to beat, military officials say.

The advantage of that haven in Pakistan, even beyond the lawless tribal realms, is that it has allowed the Taliban leadership to exercise uninterrupted control of its insurgency through the same clique of mullahs and military commanders who ran Afghanistan as a theocracy and harbored Osama bin Laden until they were driven from power in December 2001.

The Taliban’s reclusive leader, Mullah Mohammad Omar, a one-eyed cleric and war veteran, is widely believed by Afghan and Western officials to be based in Quetta, the capital of Baluchistan Province in Pakistan, near the border with Afghanistan.

He runs a shadow government, complete with military, religious and cultural councils, and has appointed officials and commanders to virtually every Afghan province and district, just as he did when he ruled Afghanistan, the Taliban claim.

But while the Taliban may be united politically, the insurgency remains poorly coordinated at operational and strategic levels, said Gen. David D. McKiernan, commander of the NATO force in Afghanistan.

Taliban forces cannot hold territory, and they cannot defeat NATO forces in a direct fight, other NATO officials say. They also note that scores of senior and midlevel Taliban commanders have been killed over the past year, weakening the insurgents, especially in the south.

Despite their losses, however, the Taliban repeatedly express confidence that the United States and its allies will grow weary of a thankless war in a foreign land, withdraw and leave Afghanistan open for a return of the Taliban to power.

Jihad does not recognize borders, the Taliban like to say, and indeed much unites the Taliban on both sides of the border. They share a common Pashtun heritage, a long-standing disregard for the Afghan-Pakistani border drawn by the British and the goal of establishing a theocracy that would impose Islamic law, or Shariah.

In fact, the dispatches of the Pakistani Taliban leader, Baitullah Mehsud, carry the symbol of the Islamic Emirate, the name the Afghan Taliban used for their government.

Mehsud and his cohort have sworn allegiance to the Afghan Taliban leader, Mullah Omar. Even Mr. bin Laden has paid tribute to Mullah Omar as Amir ul-Momineen, or Leader of the Faithful, the paramount religious leader.

To avoid jeopardizing their sanctuary or their hosts, however, the Taliban have always maintained the pretence that their leadership is based inside Afghanistan and that the insurgency is made up entirely of Afghans.

The two Afghan Taliban spokesmen, Mujahed and Qari Yousuf Ahmadi, who speak regularly by telephone to local journalists, never reveal their whereabouts. They profess sympathy for their Muslim brothers, the Pakistani Taliban, but deny that there is any joint leadership or unified strategy.