The American bombardment of Tora Bora, which had been going on for a month, yielded to saturation airstrikes on Nov. 30 in anticipation of the ground war. Hundreds of civilians died that weekend, along with a number of Afghan fighters, according to Hajji Zaman, who had already dispatched tribal elders from the region to plead with bin Laden's commanders to abandon Tora Bora. Three days later, on Dec. 3, in one of the war's more shambolic moments, Hazarat Ali announced that the ground offensive would begin. Word quickly spread through the villages and towns, and hundreds of ill-prepared men rushed to the mountain's base. The timing of the call to war was so unexpected that Hajji Zahir, one of its three lead commanders, told journalists at the time that he nearly slept through it.

On a map, it was little more than a mile from the bottom of the White Mountains to the first tier of the Qaeda caves, but the snow was thick and the slopes were steep and, for the Afghan fighters, it was a three-hour climb. They were ambushed nearly as soon as they arrived. The battle lasted for only 10 minutes before bin Laden's fighters disappeared up the slope and the Afghans limped away. Over the coming days, a pattern would emerge: the Afghans would strike, then retreat. On some occasions, a cave would change hands twice in one day. It was only on the third day of the battle that the three dozen Special Forces troops arrived. But their mission was strictly limited to assisting and advising and calling in air strikes, according to the orders of Gen. Tommy Franks, the head of U.S. Central Command, who was running the war from his headquarters in Tampa, Fla.

Even after the arrival of the Special Forces, the Afghan militias were making little headway in their efforts to assault the Qaeda caves -- largely as a result of heavier resistance than they had expected -- despite having launched simultaneous attacks from the east, west and north. They had sent none of their forces to the south, where the highest peaks of the White Mountains are bisected by the border with Pakistan. The commanders, according to news reports, argued vehemently among themselves on what the conditions on the southern side of the mountain were: some insisted it was uncrossable, closed in by snow; other commanders were far less sure.

By now, the Taliban's stronghold in Kandahar had fallen or, more correctly, had been abandoned by the soldiers of the regime. The Taliban retreat from Kandahar was emblematic of the war. None of Afghanistan's cities had been won by force alone. Taliban fighters, after intense bombing, had simply made strategic withdrawals. A number of American officers were now convinced that this was about to happen at Tora Bora, too.

One of them was Brig. Gen. James N. Mattis, the commander of some 4,000 marines who had arrived in the Afghan theater by now. Mattis, along with another officer with whom I spoke, was convinced that with these numbers he could have surrounded and sealed off bin Laden's lair, as well as deployed troops to the most sensitive portions of the largely unpatrolled border with Pakistan. He argued strongly that he should be permitted to proceed to the Tora Bora caves. The general was turned down. An American intelligence official told me that the Bush administration later concluded that the refusal of Centcom to dispatch the marines -- along with their failure to commit U.S. ground forces to Afghanistan generally -- was the gravest error of the war.

A week or so after General Mattis's request was denied, the turning point in the battle of Tora Bora came. It was Dec. 12. Hajji Zaman had by now realized that the Qaeda fighters were better armed than his men and that they were also prepared to die rather than surrender to him. He was also becoming increasingly irritated with Hazarat Ali and with the snow. And in a few days the feast of Eid al-Fitr, which ends Ramadan, would begin. The stalemate, the Americans' surrogate commander decided, simply had to end. So, through a series of intermediaries and then directly, Hajji Zaman made radio contact with some of bin Laden's commanders and offered a cease-fire. The Americans were furious. The negotiations -- to which Hazarat Ali acquiesced since he, too, was now holding secret talks with Al Qaeda -- continued for hours. By the time they came to an end, Hajji Zaman's interlocutor, hidden somewhere in the caves above, was probably bin Laden's son Salah Uddin. If the Qaeda forces surrendered, Hajji Zaman's contact said, it would be only to the United Nations. Then he requested additional time to meet with other commanders. He would be back in touch by 8 the following morning, the younger bin Laden said.

American intelligence officials now believe that some 800 Qaeda fighters escaped Tora Bora that night. Others had already left; still others stayed behind, including bin Laden. "You've got to give him credit," Gary Schroen, a former C.I.A. officer who led the first American paramilitary team into Afghanistan in 2001, told me. "He stayed in Tora Bora until the bitter end." By the time the Afghan militias advanced to the last of the Tora Bora caves, no one of any significance remained: about 20 bedraggled young men were taken prisoner that day, Dec. 17.