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War in Afghanistan (2001–2021)
October 7, 2001 – August 30, 2021· War· Asia & Pacific
Well documentedSolid records, physical evidence or scientific consensus.
The US-led war that toppled the Taliban after 9/11, then fought a 20-year insurgency, ending with the Taliban's return in 2021.
See it on the Battles & Wars map →What happened
On October 7, 2001, US and British forces began airstrikes and, with Afghan Northern Alliance fighters, drove the Taliban from Kabul by November. NATO took over the international security force in 2003. The Taliban regrouped from bases in Pakistan and waged a growing insurgency. US troops peaked near 100,000 in 2011. A 2020 US–Taliban deal set a withdrawal; Kabul fell on August 15, 2021, and the last US troops left August 30. About 2,400 US troops died; estimates of total deaths exceed 170,000.
Why it matters
It was America's longest war; its end showed the limits of building a state by force and returned Afghanistan to Taliban rule.
How we know
Audits by the US Special Inspector General for Afghanistan Reconstruction (SIGAR), the leaked 'Afghanistan Papers' (2019), NATO and UN casualty records, and journalists' reporting.
Still debated
Why the Afghan army, built at a cost of tens of billions of dollars, collapsed so fast, and whether the war could have ended differently, are debated.
Connections (5)
▸Guerrilla and insurgent warfare frustrated NATO forces in War in Afghanistan (2001–2021)Well documented
The connection
After its 2001 defeat, the Taliban rebuilt as an insurgency using roadside bombs, ambushes, intimidation of villagers and safe havens in Pakistan. NATO tried counterinsurgency, protecting the population while building an Afghan army, but the Taliban outlasted foreign forces, waiting them out until the 2021 withdrawal.
When and how
Southern and eastern Afghanistan, such as Helmand and Kandahar provinces, about 2005–2021, with the Taliban leadership based largely in Quetta, Pakistan.
How we know
NATO, US military and inspector-general reports track the insurgency's growth; the 2019 'Afghanistan Papers' show US officials privately doubted progress.
Debates and open questions
Whether a different counterinsurgency approach, or more pressure on Pakistan, could have defeated the Taliban is still argued.
▸September 11 attacks triggered War in Afghanistan (2001–2021)Well documented
The connection
Afghanistan's Taliban government sheltered bin Laden and refused US demands to hand him over. Less than four weeks after 9/11, US and British forces began strikes, after NATO had invoked Article 5, its mutual-defense clause, for the first time. The Taliban fell by December 2001, but bin Laden escaped.
When and how
Afghanistan, from October 7, 2001; NATO invoked Article 5 on September 12, 2001; the battle of Tora Bora was fought in December 2001.
How we know
US demands, Taliban responses, NATO decisions and military records are public and well documented.
Debates and open questions
Whether more negotiation might have gotten the Taliban to hand bin Laden to a third country, and how he escaped Tora Bora, are debated.
▸War in Afghanistan (2001–2021) was the proving ground for Drones and precision strikeWell documented
The connection
On the war's first night, October 7, 2001, a CIA-run Predator fired a Hellfire missile at a compound thought to hold Taliban leader Mullah Omar, the first armed-drone strike in combat. Afghanistan then became the testing ground for round-the-clock drone surveillance and strikes, flown by crews thousands of miles away via satellite.
When and how
Kandahar, Afghanistan, October 7, 2001; Predators flown by CIA and US Air Force crews, later from Creech Air Force Base in Nevada, joined by larger Reapers from 2007.
How we know
Participants' and journalists' accounts, notably Richard Whittle's Predator (2014) and Chris Woods's Sudden Justice (2015), plus US Air Force histories.
Debates and open questions
Details of the first strike, including who approved it and why Omar escaped, are still argued, and the civilian toll of drone strikes in Afghanistan is uncertain.
▸Killing of Osama bin Laden (Operation Neptune Spear) came a decade into War in Afghanistan (2001–2021)Well documented
The connection
The Afghanistan war began in 2001 largely to destroy al-Qaeda and catch bin Laden, but he fled to Pakistan. His death in 2011, as US troop numbers peaked near 100,000, removed the war's original target and strengthened the case for withdrawal, which Obama began that summer.
When and how
Launched from Jalalabad, Afghanistan, into Abbottabad, Pakistan, on the night of May 1–2, 2011, nearly ten years into the war.
How we know
The raid flew from Afghan bases, Obama's June 2011 drawdown speech cited bin Laden's death, and official war records document the timing.
Debates and open questions
Why the war went on another decade after its main target was dead, and how much Pakistan's sheltering of militants undermined it, are debated.
▸B-2 Spirit stealth bomber flew record 44-hour missions in the War in Afghanistan (2001–2021)Well documented
The connection
In the opening days of the war in October 2001, B-2s flew from Missouri to Afghanistan, bombed Taliban and al-Qaeda targets, landed at Diego Garcia in the Indian Ocean to swap crews, and flew home. One mission lasted about 44 hours, the longest combat flight on record.
When and how
Whiteman Air Force Base to Afghanistan and Diego Garcia, October 2001; crews of the 509th Bomb Wing.
How we know
Air Force records and crew interviews document the flights; the Air Force cites the 44-hour mission as a record.
Debates and open questions
Crew fatigue on such flights raised safety questions; how much the early bombing mattered versus special forces and Afghan allies on the ground is debated.