Afghanistan has been at war for more than 30 years. The Soviet Union invaded Afghanistan in 1979 to support a Communist-led coup. The Soviets withdrew after 10 years of costly fighting against Afghan insurgents armed by the United States, Pakistan and Saudi Arabia, but Afghanistan sank into civil war. The Taliban, a fundamentalist Islamic group, had taken control of most of the country by 1998.

The terrorists responsible for the 11 September 2001 attacks were financed and trained by al-Qaida, a terrorist organization based largely in Afghanistan and headed by Osama Bin Laden. The Taliban sheltered Bin Laden in return for financial and military aid in Afghanistan's ongoing civil wars. The Taliban's refusal to turn over Bin Laden and his followers following 11 September led to a United Nations-authorized international military intervention, beginning on 7 October 2001.