If he had planned to provoke a ground war in Afghanistan, Osama Bin Laden's September 11 terror strikes were perfectly timed. It is clear that the onset of the harsh Afghan winter and the Muslim holy month of Ramadan create formidable political-military obstacles to the pursuit of American goals, particularly against the backdrop of the complex and even contradictory political objectives guiding the military action. Secretary of State Colin Powell on Sunday called on the Northern Alliance to begin advancing on Kabul, with the objective not of capturing the city but of "investing" it — a military term for laying siege that required translation to a lay audience. U.S. aircraft echoed the call by bombing the Taliban frontline to the north of Kabul, Monday, although so lightly as to elicit skepticism among Alliance commanders as to the objectives of the raids. Like Secretary Powell's military jargon, current U.S. strategy in Afghanistan bears some translation for a lay audience.

The signals of the past week have been decidedly mixed when it comes to determining Afghanistan's future. Although U.S. ground troops saw their first publicized combat engagements over the weekend, their objectives are limited — to gather intelligence that may help eventually capture or kill Osama Bin Laden, and to accelerate the collapse of the Taliban regime by signaling to its fighters that the fundamentalist militia is unable to protect its territory from U.S. attack. By the array of forces it has assembled around Afghanistan, it is plain that the U.S. is not planning to launch a full-blown invasion, instead focusing on expanded special operations of the type seen around Kandahar over the weekend. The infantry, in any ground war against the Taliban, remain the troops of the opposition Northern Alliance.

Advance, but not too far

Even then, the battle plan is far from simple: Washington may want the Northern Alliance to march on Kabul, but the U.S. does not want the opposition group to actually capture it. That's because the alliance is composed primarily of fighters from the Uzbek, Tajik and Hazari minorities and would be unable to create a stable government without the consent of the Pashtun, the largest of Afghanistan's ethnic groups. The Taliban's membership is exclusively Pashtun, but it is far from representative of all Pasthun, and Washington had hoped that the bombing campaign would create significant defections from within the Taliban as well as rallying other Pashtun warlords against the Taliban. (So far, there are few signs of mass defection.) But the other crucial factor shaping the political guidelines for the conduct of the war is the U.S. reliance on Pakistan, which is firmly opposed to the Northern Alliance taking Kabul. Islamabad, instead, wants to rehabilitate the Taliban, minus Mullah Omar and Bin Laden, and give it an important role in a new government — a prospect rejected by the Northern Alliance.

Despite having to balance the competing interests of its allies in Pakistan and the Northern Alliance, the U.S. may ultimately be inclined to let the Alliance go on the offensive (with one foot on the brake) in the hope of accelerating the disintegration of the Taliban regime. The recapture of the northern town of Mazari al-Sharif from the Taliban and an advance on Kabul would certainly strike psychological blows that could potentially peel away Taliban supporters. But the Northern Alliance has so far made heavy weather of the drive to recapture its former northern stronghold at Mazari al-Sharif, where the Taliban are furthest from their heartland in the south. And right now the Taliban forces defending the approaches to Kabul are believed to be significantly larger than the Alliance forces on the Bagram front.

Saved by the snows?

The Taliban may be calculating that they will be able to survive an air campaign and put up enough of a fight on the ground to hold their lines into the winter. Even if they lose Mazari al-Sharif, they're unlikely to be routed before then. And while the winter snows that are expected within weeks won't preclude U.S. air strikes and special forces operations, they may prevent a decisive Northern Alliance offensive before next spring. Ramadan, too, will make it more difficult for the U.S. to maintain its air campaign for fear of jeopardizing both its coalition and its political objectives inside Afghanistan. And the humanitarian crisis that sees millions facing starvation will intensify with the onset of winter, adding to the political pressure on the U.S. to show restraint.

Hardly surprising, then, that U.S. political leaders are injecting a note of urgency into efforts to oust the Taliban, even as U.S. commanders emphasize that the war will likely continue into next year. The message is mixed, but not necessarily contradictory. Even if they're driven out of Mazari al-Sharif and the capital, the Taliban are unlikely to disappear from the political-military equation. But the U.S. may be hoping over the next three weeks to alter the balance of power between the Taliban and its domestic foes, keeping its special forces poised, through the winter, if necessary, to take advantage of any opportunities offered by such a power shift to go in and get Bin Laden and his henchmen.