War in Afghanistan (2001–2021)

The war in Afghanistan was a direct consequence of the September 11, 2001, terrorist attacks orchestrated by al-Qaeda, led by Osama bin Laden. The Taliban regime, which controlled Afghanistan at the time, refused to extradite bin Laden and dismantle al-Qaeda's operational bases. This refusal triggered Operation Enduring Freedom, a US-led military intervention by a coalition of nations.

The initial phase focused on rapidly toppling the Taliban government and disrupting al-Qaeda's network. The Northern Alliance, an anti-Taliban coalition, played a crucial role in this initial success, leading to the establishment of a new Afghan Interim Administration and the expulsion of the Taliban from major urban centers. The stated goals were to prevent Afghanistan from being a haven for terrorists and to foster a more stable, democratic future for the country.

Despite the initial success in removing the Taliban from power, the conflict evolved into a protracted insurgency. The Taliban, under leaders like Mullah Omar, regrouped and launched a widespread guerrilla campaign against the newly established Islamic Republic of Afghanistan and the International Security Assistance Force (ISAF), a UN-sanctioned multinational force. This asymmetric warfare involved ambushes, suicide bombings, and attacks targeting Afghan collaborators and government institutions.

By 2007, the Taliban had regained significant influence. In response, the US and its allies escalated their troop presence, peaking around 2011 with approximately 140,000 foreign troops, implementing counter-insurgency strategies like 'clear and hold' to pacify rural areas and towns. This phase was characterized by intense fighting and a constant struggle for control.

A pivotal moment occurred in May 2011 with the US covert operation in Pakistan that resulted in the killing of Osama bin Laden. While this removed the architect of the 9/11 attacks, it did not end the conflict. Instead, it marked a shift in focus for NATO allies, who began planning an exit strategy. Combat operations under ISAF formally concluded in December 2014, with security responsibilities transferred to the Afghan government.

However, the Taliban remained a potent force. Recognizing the difficulty of a purely military solution, diplomatic efforts intensified, culminating in the US-Taliban deal in February 2020. This agreement stipulated the complete withdrawal of US troops by May 2021 in exchange for Taliban assurances against harboring terrorist groups.

The US-Taliban deal, however, excluded the Afghan government, which rejected its terms. As US forces withdrew throughout 2021, the Taliban launched a swift and decisive offensive. Within months, they regained control of Afghanistan, culminating in the fall of Kabul on August 15, 2021, and the flight of President Ashraf Ghani.

The Taliban declared victory, reestablishing the Islamic Emirate. The final US military aircraft departed on August 30, 2021, ending a 20-year military presence. The war's human cost was immense, with hundreds of thousands of lives lost, including tens of thousands of civilians.

It also resulted in massive displacement, with millions becoming refugees or internally displaced persons, leaving a profound and complex legacy on Afghanistan and international relations.