United States invasion of Afghanistan
Shortly after the September 11 attacks in 2001, the United States declared the war on terror and subsequently led a multinational military operation against Taliban-ruled Afghanistan. The stated goal was to dismantle al-Qaeda, which had executed the attacks under the leadership of Osama bin Laden, and to deny Islamist militants a safe base of operations in Afghanistan by toppling the ruling Taliban government. The United Kingdom was a key ally of the United States, offering support for military action from the start of the invasion preparations. The American military presence in Afghanistan greatly bolstered the Northern Alliance, which had been locked in a losing fight with the Taliban during the Third Afghan Civil War since 1996. Prior to the beginning of the United States' war effort, the Taliban had seized around 85% of Afghanistan's territory as well as the capital city of Kabul, effectively confining the Northern Alliance to Badakhshan province and smaller surrounding areas. The American-led invasion on 7 October 2001, marked the first phase of what would become the 20-year-long war in Afghanistan.
After the September 11 attacks, American president George W. Bush demanded that the Taliban government extradite Osama bin Laden to the United States and also expel al-Qaeda militants from Afghanistan; bin Laden had been active in Afghanistan since the Soviet–Afghan War and was already wanted by the Federal Bureau of Investigation for his role in the 1998 United States embassy bombings. The Taliban declined to extradite bin Laden and further ignored demands to shut down terrorist bases or extradite other suspected terrorists. In response, the United States launched Operation Enduring Freedom on 7 October 2001, alongside the United Kingdom. The two countries were later joined by a large multinational force, made up of multiple NATO members and two of their major non-NATO allies, as well as Afghanistan's local Northern Alliance. The invasion effort made rapid progress for the next two months as the coalition captured Kabul on 13 November and toppled the Taliban by 17 December, after which international military bases were set up near major cities across the country. However, most members of al-Qaeda and the Taliban were not captured: during the Battle of Tora Bora, several fighters including bin Laden, the founder of al-Qaeda escaped into neighboring Pakistan or otherwise retreated to remote regions deep within the Hindu Kush.
In December 2001, the United Nations Security Council established the International Security Assistance Force to oversee military operations in Afghanistan and also train the new Afghan National Security Forces. At the Bonn Conference that same month, Hamid Karzai was selected to lead the Afghan Interim Administration. Simultaneously, the Taliban's founding leader Muhammad Umar reorganized the movement to wage asymmetric warfare against the coalition, and by 2002, the group had launched an insurgency against the American-led war effort. Protracted fighting continued for the next two decades, and by mid-2021, the international coalition and the United States had begun to withdraw from the country amidst a nationwide Taliban offensive. In August 2021, the Taliban captured Kabul and toppled the Afghan government, re-establishing their rule in the form of a second Islamic emirate.
Background
In 2001, Afghanistan had been at war for over 20 years. The communist People's Democratic Party of Afghanistan seized power in 1978, and its policies sparked a popular uprising. The Soviet Union, sensing PDPA weakness, intervened in 1979 to support the regime. The Soviet entry into Afghanistan prompted its Cold War rivals, especially the United States and Saudi Arabia, to support rebels fighting against the Soviet-backed PDPA. While the secular and socialist government controlled the cities, religiously motivated mujahidin held sway in much of the countryside. The most important mujahidin commander was Ahmad Shah Massoud, who led the well-organized Tajik forces. The American Central Intelligence Agency worked closely with Pakistan's Inter-Service Intelligence to funnel foreign support for the mujahidin. The war also attracted Arab volunteers, known as "Afghan Arabs", including Osama bin Laden.After the withdrawal of the Soviet military from Afghanistan in February 1989, the PDPA regime collapsed in 1992. In the resulting power vacuum, the mujahidin leaders vied for dominance in a civil war from 1992 to 1996. By then, bin Laden had already left the country. The United States' interest in Afghanistan also diminished. In 1994, a Pashtun mujahid named Muhammad Umar founded the Taliban movement in Kandahar. His followers were religious students and sought to end warlord rule through strict adherence to Islamic law. By the end of 1994, the Taliban had captured all of Kandahar Province.
Taliban vs. Northern Alliance (1996–2001)
In 1996, with military support from Pakistan and financial support from Saudi Arabia, the Taliban seized Kabul and founded the Islamic Emirate of Afghanistan. They imposed their fundamentalist interpretation of Islam in areas under their control, issuing edicts forbidding women to work outside the home or attend school and requiring them to abide by harsh rules on veiling and seclusion.After the Taliban takeover of Kabul, Massoud retreated north to his native Panjshir Valley and formed a resistance movement against the Taliban, called the United Front or the Northern Alliance. In addition to Massoud's Tajik force, the United Front included Uzbeks under the former PDPA general Abdul Rashid Dostum and Hazara factions. The Northern Alliance received varying degrees of support from Russia, Iran, and India. Like the Taliban, Massoud also raised money by trafficking drugs. By 2001, the Taliban controlled 80% of the country, with the Northern Alliance confined to the country's northeast corner.
Al-Qaeda
After nearly five years of shelter, bin Laden was expelled from Sudan in 1996 and arrived in Jalalabad, Afghanistan. He had founded al-Qaeda in the late 1980s to continue jihad after the end of the Soviet–Afghan War. He moved al-Qaeda's operations to eastern Afghanistan and developed a close relationship with the Taliban. However some key Taliban members, such as the foreign minister Wakil Muttawakil, disapproved of the alliance with al-Qaeda because bin Laden's terrorist activities were complicating the Taliban's quest for international recognition of their government. In 2000, Muhammad Umar visited bin Laden and forbade him from attacking the United States while he was a guest of the Taliban. During the 1990s, the CIA and Delta Force planned several operations to kill or capture bin Laden, but President Bill Clinton never ordered them to proceed.Change in U.S. policy towards Afghanistan
During the early years of the Clinton administration, the US had no clear policy toward Afghanistan. The 1998 US embassy bombings, however, masterminded by al-Qaeda, provoked President Clinton to order missile strikes on militant training camps in Afghanistan; bin Laden was indicted for his involvement in the bombings. In 1999 both the US and the United Nations enacted sanctions against the Taliban in United Nations Security Council Resolution 1267, which demanded the Taliban surrender bin Laden for trial in the US and close all terrorist bases in Afghanistan. At the time, the only collaboration between Massoud and the US was an effort with the CIA to trace bin Laden. The US provided no support for Massoud's fight against the Taliban.A change in US policy was effected in early September 2001. The Bush administration agreed on a plan to start supporting Massoud. On 10 September, a meeting of top national security officials agreed that the Taliban would be presented with an ultimatum to hand over bin Laden and other al-Qaeda operatives. If the Taliban refused, the US would provide covert military aid to anti-Taliban groups to attempt to overthrow the Taliban.
Military situation on the eve of the 9/11 attacks
On 9 September 2001, two al-Qaeda members posing as journalists killed Massoud by detonating a bomb hidden in their video camera battery belt during an interview. Muhammad Fahim became the new leader of the Northern Alliance. The Alliance had 15,000–20,000 fighters distributed across five locations. On the Kabul front, Taliban and Northern Alliance forces faced each other from trenches across the Shomali Plain. The Takhar front extended from the Tajikistan border in the north to Parwan in the south, near Kabul. Dostum's forces were located south of Mazar-i-Sharif, the Hazaras under Muhammad Mohaqiq were in the central Hazarajat region, and Ismail Khan was near Herat.The Taliban's military commander in the north was Mohammad Fazl. The Taliban military comprised approximately 45,000 Afghans and 2,700 foreign fighters, which included al-Qaeda's 055 Brigade. According to military analyst Ali Jalali, the 055 Brigade was only 400–600 strong, but its ties to bin Laden made it politically important. The foreign fighters included Arabs as well as Kashmiris, Chechens, Uzbeks, and Uyghurs. Several hundred officers from Pakistan's ISI were stationed in Afghanistan advising the Taliban. By mid-October, approximately 10,000 Pakistani volunteers crossed the border to augment the Taliban's forces. The volunteers were mostly madrasa students, some as young as 14.
Both sides primarily used Russian military equipment. The Northern Alliance had 14.5mm heavy machine guns, Russian artillery, T-72 tanks, and BMP-1 armored vehicles retrofitted with rocket pods from Soviet combat helicopters. Dostum's Uzbeks used horses for transportation. The Northern Alliance had 18 helicopters and three fixed-wing planes, used mostly for logistical purposes. The Taliban's equipment was similar to that of the Northern Alliance, and they also had Stinger missiles donated by the United States to the mujahidin during the Soviet–Afghan War. They relied on pickup trucks for mobility and operated as a "motorized light force." They had about 40 combat aircraft, operated by ex-PDPA pilots.
Both sides had a history of human rights abuses: Uzbeks and Hazaras had "massacred hundreds of Taliban prisoners and killed Pashtun villagers in the north and around Kabul", and the Taliban killed 5,000–8,000 civilians after they captured Mazar-i-Sharif in 1998. Afghanistan also faced a serious humanitarian crisis in 2001 due to drought; according to the United Nations, 5 million Afghans were in need of humanitarian aid that year and 3.8 million could not survive without UN food aid.