Last week Mazar-e Sharif became a battleground–and a graveyard–once again. As American warplanes bombarded Taliban front lines, the Northern Alliance launched a long-awaited assault on the city. Tanks and armored vehicles supported by infantry and warriors on horseback advanced north through outlying villages toward the city, across a moonscape of bomb craters, broken bunkers, a scattering of dead Taliban soldiers and discarded equipment. By Friday evening, thousands of dirt-smeared Taliban fighters had abandoned their bunkers and tunnels and evacuated Mazar-e Sharif. “The Taliban didn’t put up a fight,” said Mohammad Ashraf Nadeem, a spokesman for one senior Northern Alliance commander, Ostad Atta Muhammad. “They ran away.”

The Taliban left behind only their wounded in the city’s hospitals and a smattering of recently arrived Pakistani sympathizers to surrender. “We have the airport, we have Mazar, we have everything,” exulted Gen. Rashid Dostum, the Uzbek warlord who commands the Northern Alliance’s forces in the northwest and who arrived on horseback. Hours later the Taliban-controlled Afghan Islamic Press confirmed that opposition troops had entered the city “after heavy American bombing.” Hundreds of Taliban troops were killed, to only about 30 Northern Alliance dead, Mohammed Hashan-Saad, the Northern Alliance’s ambassador to Uzbekistan, said Saturday. Coordinated attacks launched from the southeastern and southwestern flanks of alliance territory south of Mazar also captured strategic towns as much as 125 miles to the east and west of Mazar, he said. Confirmation from the Pentagon was slow in coming, but spokeswoman Victoria Clarke called the news “encouraging.”

It’s too early to say this is a turning point. Thousands of Taliban troops escaped unscathed from Mazar and could launch a counteroffensive, as they did three years ago. U.S. officials were working hard to avert that. Rear Adm. Mark Fitzgerald, commanding officer of the USS Theodore Roosevelt battle group, said Saturday that he had launched scores of strike aircraft to “try to take out as much as we can as they try to fall back and regroup.” In any case, the routing of the Taliban around Mazar-e Sharif was America’s first tangible victory in the war against Osama bin Laden–and a huge morale boost at a time of deepening anxiety about the campaign’s progress. With the Muslim holy month of Ramadan looming next week, and a chorus of critics in the Muslim world denouncing the U.S. bombing as a futile effort that was only killing civilians, Washington was becoming desperate for a battlefield success that would sway the tide of opinion.

If the Northern Alliance occupation of Mazar-e Sharif holds, it will be a vindication of the Pentagon’s “Northern Strategy” of using the alliance as proxy ground troops while pulverizing the Taliban with pinpoint airstrikes. It could also be a major step toward moving on the capital of Kabul and ousting the Taliban mullahs from power, which the Bush administration sees as critical to “draining the swamp” that harbors bin Laden (who warned in a Pakistani newspaper interview published Saturday that he had nuclear and chemical weapons). From Mazar, the allies can establish a land route to neighboring Tajikistan, bring in supplies and prepare for an advance across the north and to the capital, Kabul.

A serious assault on Kabul would probably not take place until the spring. But according to Pentagon sources, U.S. commander Gen. Tommy Franks hopes to exploit the current momentum to launch a series of airborne assaults into the warmer regions of southern Afghanistan in the coming months–using U.S. Marines along with Special Forces as raiding parties on Taliban strongholds. Franks has asked for 3,000 Marines to join a 2,200-man expeditionary force stationed in the Arabian Gulf aboard the amphibious assault vessel Peleliu and for scores of strike aircraft based in Tajikistan. NEWSWEEK has learned that there is a debate about what comes next. Franks wants heavy U.S. reinforcements standing by; he is concerned that, if left to the Northern Alliance, things could go to “hell in a handbasket in a hurry,” a colleague of his told NEWSWEEK. The general has requested a brigade of the First Cavalry Division–about 2,500 men, 100 tanks, Apache attack helicopters and other artillery–from Fort Hood, Texas. Franks faces resistance from his Pentagon superiors; Defense Secretary Donald Rumsfeld still wants most of the ground fighting to be done by Afghans and wants to wait a “few more weeks” on Franks’s request, says one source. Franks, however, is said to believe that the Northern Alliance is not capable of attacking the strongholds of Kandahar and Jalalabad without major U.S. support.

The defeat at Mazar was a psychological setback for the Taliban as well. Their retreat has shattered the popular perception throughout Afghanistan that the Taliban were stalwart in the face of America’s high-tech assault. “The loss of Mazar-e Sharif has broken their superman image,” says a Western diplomat in Islamabad. In Afghanistan, where loyalties switch with the wind, warlords across the north who joined the Taliban juggernaut in the 1990s may now abandon it–there were some reports of defections over the weekend. Still, the Taliban appears in control of the south, where fierce U.S. bombing and mounting civilian casualties have galvanized anti-American sentiment. And U.S.-backed attempts by opposition Pashtuns to persuade Taliban officials to defect have made little progress, stymied in part by a formidable intelligence network reaching deep inside Pakistan.

For weeks, the reports from Mazar-e Sharif had been as discouraging as other news from the many fronts of the war on terror. Dostum and his fellow commanders repeatedly claimed to have advanced to the city’s outskirts–only to be beaten back into the mountains. But two weeks ago, after a meeting between Franks and alliance commander General Fahim in the Tajik capital of Dushanbe, the United States began precision bombing against Taliban frontline positions. U.S. Special Forces air controllers, shuttled by helicopter to the field headquarters of the alliance generals, coordinat- ed airstrikes with ground-troop advances. C-130 cargo planes and helicopters flying out of Khanabad air base in Uzbekistan kept the 10,000 alliance soldiers supplied with drops of ammunition, winter gear, even fodder for their horses.

Sources inside Mazar-e Sharif reported that the Taliban suffered more than 300 dead and 500 wounded in recent days. The Afghan, Arab and Pakistani fighters who form the Taliban forces, their ears still ringing from the punishing bomb blasts, withdrew as quickly as they could toward the foothills, pursued by American warplanes. In the chaos, Tajik and Uzbek citizens in outlying villages reportedly rose up and killed Taliban fighters. More than 1,000 other Taliban reportedly defected to the alliance.

The allies must now secure their hold on Mazar-e Sharif, take control of the airports and clear the road north to the border with Uzbekistan. The U.S. military can then use the airport as its in-country base for the winter, and begin trucking convoys of relief and military supplies to Northern Alliance forces and 400,000 internally displaced people in the north. With the spring thaw, the alliance could push eastward toward the strategic city of Konduz, 90 miles from Mazar. If Konduz falls, the 10,000 Taliban troops massed around the northeast stronghold of Taloqan would lose their main supply link. The capture of Taloqan would join the divided Northern Alliance forces, giving them complete control of the north, easier lines of communication and numerous airfields. (On Saturday, U.S planes began their most intensive bombing yet around the northern town of Dasht-e Qala, about 50 kilometers north of Taloqan, observers on the ground said.)

Once the region around Mazar-e Sharif is secured, the push toward Kabul can also begin in earnest. The Northern Alliance needs to capture just one town on the road from Mazar to the capital, then clear the badly damaged Salang Tunnel, which burrows for more than a mile through the mountains before the road drops down to the Kabul plain. For now, Northern Alliance forces grouped around Baghram air base, just north of Kabul, have had to truck in supplies through the Panjshir Valley over a mountain trail impassable in the winter.

But capturing the predominantly Pashtun south is likely to be far more difficult. As positive as the news from the north was, in the south the opposition was still reeling last week from the near capture of prominent Afghan opposition leader Hamid Karzai, who had crossed into Afghanistan from Quetta last month to win over tribal leaders in remote mountain villages. Instead, Taliban forces surrounded his party and engaged them in a six-hour gun battle; the Pentagon said Karzai was airlifted to safety in Pakistan by U.S. helicopters. The Taliban has been bolstered throughout the country by grassroots Pakistani support. The United States has allocated $73 million to shore up Pakistan’s border security and thus stop the flow of fighters and weapons in and out of Pakistan, but Pakistani President Pervez Musharraf knows he risks armed rebellion if he attempts to intervene. “Pakistan cannot stop these fighters from going in,” he admitted last week.

As the military pressure intensifies, Mullah Mohammed Omar and his combat-tested Afghan and Arab field commanders may soon have to make a decision: whether to wage a guerrilla war in the rubble of Kabul or withdraw to their Pashtun strongholds in southern and eastern Afghanistan. Barring a wave of Taliban defections and a significant–and bloody–U.S.-led ground assault, the Taliban fighters could conceivably hold out there for a long time and continue to harbor Al Qaeda. A divided Afghanistan could set the stage for a bloody civil war. Mullah Omar is on record as saying that if the Taliban were driven out of Kabul, the forces would regroup and “put up a resistance for 20 years or more” from the Pashtun heartland. The war on terror, it is clear, is still likely to be a long one.