American Special Forces, CIA paramilitary teams, and Afghan militia fighters pressed a large-scale assault on cave and tunnel complexes in the White Mountains of Tora Bora, believed to be sheltering Osama bin Laden and hundreds of al-Qaeda fighters. Heavy bombing and ground fighting continued for days, but bin Laden ultimately slipped across the border into Pakistan, a failure that would shape the next decade of the war on terror.
Tora Bora's honeycomb of natural caves and Soviet-era tunnels, carved into the mountains near the Khyber Pass, had long served as a mujahideen stronghold, and bin Laden had personally helped fortify it during the anti-Soviet jihad of the 1980s. By early December 2001, intelligence indicated he was hiding there with a core group of fighters.
Rather than commit large numbers of American ground troops, U.S. commanders relied heavily on Afghan militia forces under warlords like Hazrat Ali, backed by American air power and small special operations teams calling in strikes. Critics later argued this decision, driven partly by a desire to keep the American footprint light, gave bin Laden's forces gaps to escape through mountain passes into Pakistan's tribal areas.
By mid-December, most of the fighting had petered out and it became clear bin Laden had evaded capture, a fact not widely confirmed for years. The failure to capture or kill him at Tora Bora is often cited as one of the most consequential missed opportunities of the entire war in Afghanistan, allowing al-Qaeda's leadership to regroup and persist for another decade.