2001 — Present

The War on Terror

$8Tand counting

Twenty years, two wars, and a bill that added up to roughly $8 trillion — most of it borrowed.

The attacks of September 11, 2001 launched two decades of war across Afghanistan, Iraq, and beyond. Brown University's Costs of War project totals the cost near $8 trillion and the death toll in the hundreds of thousands — much of it financed by debt whose interest will run for decades. This adds up what rarely gets summed: the dollars, the casualties, and the surveillance and legal changes at home — and sets the security rationale beside the price.

Total estimated cost

$8.0T

Through FY2022 plus veterans' care to 2050 (Costs of War, $8.043T)

U.S. service-member deaths

7,073

Five post-9/11 operations (DoD DCAS, as of July 2026)

Direct war deaths, all sides

940,000+

2001 — 2023, incl. 432,000+ civilians (Costs of War)

Longest war — Afghanistan

19y 10m

Oct 7, 2001 — Aug 30, 2021. The longest in U.S. history.

Future interest on war debt

$6.5T

Through 2050, on top of the $8T (Costs of War)

The post-9/11 wars · 2001 — present

Hover any milestone for context.

Attack / invasionEscalationLaw / drawdownWar's end

Sixty words, three days, twenty-five years

The legal architecture of the entire era was built in about seventy-two hours. On September 14, 2001 — with the rubble still burning — Congress passed the Authorization for Use of Military Force, sixty words granting the president power to use force against whoever "planned, authorized, committed, or aided" the attacks. It passed 420-1 in the House and 98-0 in the Senate. Rep. Barbara Lee of California cast the only no vote, warning that Congress was signing a blank check.

Four presidents from both parties have since invoked that authorization to justify operations in at least 19 countries — including against organizations, like ISIS, that did not exist in 2001. It has never been repealed. Congress has not voted to authorize the wars it is still funding.

Two wars, two very different shapes

Afghanistan began first and ended last: October 7, 2001 to August 30, 2021 — 19 years and 10 months, the longest war in American history. It achieved its stated objective in 2011 when bin Laden was killed in Pakistan, then continued for another decade. It ended with the Taliban back in power.

Iraq was the more intense and, for U.S. forces, far the deadlier: 4,598 American military deaths in Iraq against 2,324 in Afghanistan. It was launched on a premise — weapons of mass destruction — that turned out not to exist, and it had no connection to the 9/11 attacks. Its spending peaked in FY2008 during the surge, the single deadliest stretch of the whole era. The U.S. left in 2011 and came back three years later to fight ISIS, an organization the invasion itself had helped create.

Why it never quite ends

The withdrawal from Kabul in 2021 is the closest thing to an ending the war on terror has. But Operation Inherent Resolve — the anti-ISIS mission launched in 2014 — is still running in 2026. The 2001 AUMF is still law. Guantánamo still holds fifteen men. And the two largest financial obligations, veterans' care and interest on the borrowing, are mostly ahead of us rather than behind. The fighting has a date. The bill does not.