AUMF and the 2001 War on Terror Authorization

What Is an AUMF

An AUMF, or authorization for use of military force, is a law in which Congress approves a war without formally declaring one. It names who the president may fight, and it satisfies the War Powers Act, so no 60-day clock runs against it. The one most people mean is the 2001 AUMF, passed after the September 11 attacks. It has no end date and no geographic limit.

An AUMF and a declaration of war have the same legal effect at home: both are Congress saying yes. The difference is scope. A declaration names an enemy nation. An AUMF can name anyone Congress chooses, and the 2001 version let the president choose.

What the 2001 AUMF Says

The operative part of the 2001 AUMF is one sentence, and nearly every fight over it comes down to one clause: “he determines.” Section 2(a) authorizes the president to use “all necessary and appropriate force against those nations, organizations, or persons he determines planned, authorized, committed, or aided the terrorist attacks that occurred on September 11, 2001, or harbored such organizations or persons” (P.L. 107-40).

Read plainly, that means al-Qa’ida, which carried out the attacks, and the Taliban, which sheltered it. The text has no expiration date, no list of countries, and no requirement that the president come back to Congress. It does require reports under the War Powers Act, which is why a paper trail of citations exists at all.

Barbara Lee, a Democrat from Oakland, cast the only no vote in either chamber, as the House roll call records. The Senate vote was 98-0, with two senators absent (Senate).

Who the 2001 AUMF Covers Now

The government reads the 2001 AUMF to reach al-Qa’ida, the Taliban and their “associated forces,” a phrase that is not in the law. Presidents from Bush to Trump have used it, and courts have accepted it in detention cases. In a 2016 report to Congress, the Obama administration set out two tests: a group must be an organized armed group that entered the fight alongside al-Qa’ida or the Taliban, and it must be a co-belligerent against the United States or its partners (2016 frameworks report).

That report is also the last public list of who is covered. Every annual report since, including the one filed in February 2026, lists “No change” to the groups (2026 frameworks report).

ISIS is the hardest case, because it split from al-Qa’ida in 2014 and has fought it since. The administration’s answer was that ISIS began as al-Qa’ida in Iraq, fought the United States under that name, and is the same enemy under a new one, and the 2016 report spent a full section making that case. No court has ruled on the question.

Where the 2001 AUMF Has Been Used

By 2021, presidents had cited the 2001 AUMF for military activity in 22 countries, and most of it was not combat. Brown University’s Costs of War project read every public presidential notification and sorted them by the kind of activity each one described (Costs of War).

8

13

1

• Airstrikes and combat (8 countries) Afghanistan, Djibouti, Iraq, Libya, Pakistan, Somalia, Syria, Yemen
• Support for partner forces (13 countries) Training, advising, surveillance and equipment, from Georgia to Niger
• Detention (1 country) Guantanamo Bay, Cuba

Source: Stephanie Savell, Costs of War, Brown University, December 14, 2021, summary table. Countries named in public presidential citations of the 2001 AUMF, by the activity described.

The support category is where the authorization spread quietly. It covers U.S. troops training, advising and flying surveillance for partner militaries, in places like Chad, Cameroon and Lebanon. The line between support and combat is thin. Four U.S. soldiers were killed in an ambush in Niger in October 2017, in a mission the government had described to Congress as support (CRS memo).

The same study found U.S. forces fighting in places the government never tied to the AUMF at all. It cites investigative reporting on U.S. combat in Mali and evidence of ground combat in Tunisia, neither reported to Congress under the authorization.

The combat citations did not stay in Afghanistan. They moved across the Middle East and Africa over two decades, and several restarted after gaps of years.

1. Afghanistan 2001–2021
2. Djibouti 2002–2010
3. Yemen 2002–2006
4. Pakistan 2003–2003
5. Iraq 2004–2009
6. Somalia 2007–2007
7. Somalia 2012–2021
8. Yemen 2012–2021
9. Libya 2013–2013
10. Iraq 2014–2021
11. Syria 2014–2019
12. Djibouti 2015–2021
13. Libya 2015–2019

2005201020152020

Years each country appeared in AUMF citations for airstrikes or combat

Item	Began	Ended	Length
Afghanistan	January 1, 2001	December 31, 2021	20 years
Djibouti	January 1, 2002	December 31, 2010	8 years
Yemen	January 1, 2002	December 31, 2006	4 years
Pakistan	January 1, 2003	December 31, 2003	under 1 year
Iraq	January 1, 2004	December 31, 2009	5 years
Somalia	January 1, 2007	December 31, 2007	under 1 year
Somalia	January 1, 2012	December 31, 2021	9 years
Yemen	January 1, 2012	December 31, 2021	9 years
Libya	January 1, 2013	December 31, 2013	under 1 year
Iraq	January 1, 2014	December 31, 2021	7 years
Syria	January 1, 2014	December 31, 2019	5 years
Djibouti	January 1, 2015	December 31, 2021	6 years
Libya	January 1, 2015	December 31, 2019	4 years

Source: Costs of War, Brown University, December 14, 2021. Each bar is a span of years in which presidential notifications cited the 2001 AUMF for strikes or combat in that country; a country cited in two separate periods has two bars.

Yemen and Somalia show the pattern. Each was cited early in the Bush years, dropped out, and came back in 2012 for a decade of strikes against al-Qa’ida’s Yemen branch and al-Shabaab, groups the 2016 report added by name.

How the 2001 AUMF Grew

The 2001 AUMF grew by executive reading, not by any new vote. It passed in 2001, was read to cover detention by 2004, and was stretched to ISIS in 2014. Congress repealed the Iraq authorizations beside it in 2025 and left it standing.

1. 2001 Congress passes the AUMF House 420-1, Senate 98-0 on September 14. Signed September 18.
2. 2004 Court upholds detention under it Hamdi v. Rumsfeld: the AUMF allows holding enemy fighters, but citizens get a hearing.
3. 2012 Congress affirms detention power The 2012 defense bill writes AUMF detention authority into law.
4. 2014 ISIS added by reading The Obama administration cites the AUMF for strikes in Iraq and Syria.
5. 2016 Covered groups made public A White House report lists 8 groups; 4 formed after 2001.
6. 2021 Afghanistan war ends U.S. forces leave in August. The AUMF stays in force.
7. 2025 Iraq authorizations repealed The 1991 and 2002 Iraq AUMFs end December 18. The 2001 AUMF does not.
8. 2025 Nigeria strikes December 25 strikes on ISIS sites cite the 2001 AUMF.

Sources: House and Senate roll calls, September 14, 2001; Hamdi v. Rumsfeld, 542 U.S. 507 (2004); 2016 and 2026 White House frameworks reports; U.S. Code notes to 50 U.S.C. 1541.

The 2001 AUMF, from 9/11 to today: 2001: Congress passes the AUMF (House 420-1, Senate 98-0 on September 14. Signed September 18.). 2004: Court upholds detention under it (Hamdi v. Rumsfeld: the AUMF allows holding enemy fighters, but citizens get a hearing.). 2012: Congress affirms detention power (The 2012 defense bill writes AUMF detention authority into law.). 2014: ISIS added by reading (The Obama administration cites the AUMF for strikes in Iraq and Syria.). 2016: Covered groups made public (A White House report lists 8 groups; 4 formed after 2001.). 2021: Afghanistan war ends (U.S. forces leave in August. The AUMF stays in force.). 2025: Iraq authorizations repealed (The 1991 and 2002 Iraq AUMFs end December 18. The 2001 AUMF does not.). 2025: Nigeria strikes (December 25 strikes on ISIS sites cite the 2001 AUMF.).

2001: Congress passed the authorization on September 14, three days after the attacks, and President Bush signed it on September 18. U.S. strikes in Afghanistan began October 7.

2004: In Hamdi v. Rumsfeld, the Supreme Court held that the AUMF allows the military to detain fighters captured in the conflict, while a plurality ruled that a U.S. citizen held that way must get a real chance to contest it before a neutral decision-maker.

2012: The defense bill for 2012 stated in law that the AUMF includes power to detain members of al-Qa’ida, the Taliban and associated forces, as the 2016 frameworks report describes.

2014: On September 23, 2014, President Obama told Congress that strikes against ISIS in Iraq and Syria rested in part on the 2001 AUMF, a reading the 2016 report later spelled out (2016 frameworks report).

2016: The December 2016 frameworks report named the groups the government was targeting under the AUMF. It remains the most recent public list.

2021: The last U.S. forces left Afghanistan in August 2021, ending the war the authorization was written for. The law itself did not change.

2025: Section 8370 of the defense bill signed December 18, 2025 repealed the 1991 Gulf War and 2002 Iraq War authorizations (P.L. 119-60). On December 25, the United States struck two ISIS sites in Sokoto State, Nigeria, with Nigeria’s consent, and the White House told Congress the strikes were “pursuant to the 2001 AUMF” (2026 frameworks report).

Of the four war authorizations in our War Powers Act explainer’s chart of how long each lasted, the 2001 AUMF is the only one still in force.

The AUMF in 2025 and 2026

In 2025 the president relied on the 2001 AUMF for three kinds of operations and on his own constitutional power for four others, including the strikes on alleged drug boats. The annual frameworks report filed in February 2026 draws that line itself.

That split matters because an AUMF is a vote Congress already took, while Article II is a claim Congress never approved. The boat strikes are the clearest example. Some published accounts have described them as AUMF operations, but the report says President Trump ordered them “pursuant to his constitutional authority as Commander in Chief,” against drug trafficking groups designated as terrorist organizations. The same holds for the Iran war that began in 2026: the administration’s reports cited only the president’s constitutional power, as our War Powers Act explainer covers.

Where the 2001 AUMF and the Fights Over It Stand

As of September 26, 2026

• 2001 AUMF (P.L. 107-40) Law, no end date

  In force. The February 2026 report lists no change to its scope or the groups it covers. (source)

• 1991 and 2002 Iraq AUMFs Ended, repealed

  Repealed by section 8370 of the defense bill signed December 18, 2025 (P.L. 119-60). (source)

• H.R. 6751, Sunset for the 2001 Authorization for Use of Military Force Act Proposal, in committee

  Repeals the 2001 AUMF 240 days after enactment. 18 cosponsors, 3 of them Republicans. Referred to the House Foreign Affairs Committee December 16, 2025. No action since. (source)

• Strikes in Nigeria Agency action, cites the AUMF

  December 25, 2025 strikes on two ISIS sites in Sokoto State, reported to Congress as authorized by the 2001 AUMF. (source)

• Caribbean and Pacific boat strikes Agency action, Article II, not the AUMF

  Ongoing since September 2025. The White House cites the president's constitutional power, not the 2001 AUMF. (source)

Source: White House frameworks reports (2016, 2026); govinfo bill status for H.R. 6751 and H.R. 1488; U.S. Code notes to 50 U.S.C. 1541

The Iraq repeal shows what it takes. The standalone bill, H.R. 1488, drew 36 cosponsors, 13 of them Republicans, and the repeal finally passed inside the annual defense bill. The 2001 sunset bill has 18 cosponsors, including Republicans Thomas Massie, Morgan Griffith and Eli Crane.

The Honest Disagreement Over the 2001 AUMF

Supporters of keeping the 2001 AUMF say repeal would leave U.S. forces without clear authority against groups still plotting attacks. Administrations of both parties have kept every group on the 2016 list, and the argument for keeping the law is that repeal without a replacement would push future strikes onto the president’s constitutional power alone, which Congress has never approved.

Critics say the authorization has become a standing license Congress never meant to give. They point to the groups added by executive reading, the countries added without a vote, and the fact that the enemy named in 2001, al-Qa’ida’s leadership in Afghanistan, is largely gone. The sunset bill pairs repeal with a 240-day delay so Congress can write a narrower authorization first if it chooses.

Both sides agree on one fact: Congress has not voted on the scope of the war against these groups since 2001.

• An AUMF is not a declaration of war. It is narrower in some ways and broader in others, and it does not trigger the laws that take effect only in a declared war.
• The AUMF does not cover every strike a president orders. The 2025 boat strikes and the 2026 Iran war rest on claimed constitutional power, a separate question covered in our War Powers Act explainer.
• Repealing the Iraq authorizations did not end operations in Iraq. The February 2026 report says U.S. forces there and in Syria now operate under the 2001 AUMF.
• The AUMF is not a law for use at home. Deploying troops inside the country is governed by the Insurrection Act and the Posse Comitatus Act.

Frequently Asked Questions

What does AUMF stand for?

Authorization for Use of Military Force. It is a law in which Congress approves military action against a named enemy without a formal declaration of war.

Is the 2001 AUMF still in effect?

Yes. Congress repealed the 1991 and 2002 Iraq authorizations in December 2025 but left the 2001 AUMF in place. It has no expiration date.

Did the 2001 AUMF authorize the Iraq War?

No. The 2003 invasion rested on a separate 2002 authorization aimed at Saddam Hussein’s government. That law was repealed on December 18, 2025.

Who voted against the 2001 AUMF?

One member of Congress: Rep. Barbara Lee of California. The House vote was 420-1, and the Senate vote was 98-0.

What You Can Do

1. Ask your representative to cosponsor H.R. 6751. It would repeal the 2001 AUMF 240 days after enactment, giving Congress time to decide what, if anything, should replace it. Check the cosponsor list first, and thank anyone already on it.

2. Ask your senators whether they would back a repeal in the Senate. The Iraq repeal succeeded inside the annual defense bill, so ask whether they would offer or support a 2001 AUMF sunset amendment to the next one.

3. Read the annual frameworks report. The White House must tell Congress each year which operations rest on the AUMF. The calendar-2025 report is three pages.

4. Learn the related powers. Presidents can also act through national emergencies, and the Supreme Court’s presidential immunity ruling shapes what happens afterward.

5. Write your members of Congress. Our letter-writing guide shows how to make a short, specific ask about the AUMF land with a congressional office.