The legacy of 9/11

Two decades after September 11, the shocking and tragic attacks continue to shape American politics and foreign policy. In the months following the attacks, the U.S. passed the Patriot Act, checking civil liberties in the name of security; drove Al Qaida from Afghanistan and ousted the Taliban from power, launching what would become the country’s longest sustained military campaign; and enacted the Homeland Security Act, resulting in the Department of Homeland Security—now the third largest Cabinet department. In the years since, 9/11 has transformed the U.S. government and Americans’ attitudes about safety, privacy, and the nation’s role in global affairs. The impacts of the war on terror have reverberated around the world. With the United States’ withdrawal from Afghanistan this year, the Taliban have once again seized power there, with agonizing implications for Afghans and the world.

Today, extremist threats, technology, and the international order have evolved, repression and regional conflict continue to destabilize the Middle East, and the COVID-19 pandemic has brought another inflection point. How can we apply what we have learned over the past two decades? Below, Brookings experts offer reflections and recommendations.

U.S government and politics

The Statue of Liberty and One World Trade Center are seen as the Tribute in Light shines in downtown Manhattan.

Terrorism & Extremism I hadn’t the slightest idea my life would change after 9/11

Shadi Hamid

September 20, 2021

An empty hallways in a cellblock in the US military prison at Guantanamo Bay

Human Rights & Civil Liberties It’s time for a reckoning on torture

Noha Aboueldahab

September 15, 2021

One World Trade Center lit in Blue to honor the people who perished during September 11, 2001 terror attack in New York City. (Photo by Ron Adar / SOPA Images/Sipa USA)No Use Germany.

U.S. Foreign Policy 20 years after 9/11, the US is again in a great power confrontation

James Goldgeier

September 10, 2021

Heavily armed Strategic Response Unit officers of the NYPD are seen stationed in front of the Empire State Building on Wednesday, April 22, 2020 in New York City. Gov. Andrew Cuomo said Wednesday hes enlisted former Mayor Mike Bloomberg to help create a tracing army that will find people infected with the coronavirus and get them into isolation. With 474 virus related deaths on Tuesday, New York state has now recorded more than 15,000 since the outbreak began. (Photo by Louis Lanzano/Sipa USA)/Sipa USANo Use UK. No Use Germany.

Crime, Justice & Safety How 9/11 helped to militarize American law enforcement

Rashawn Ray

September 9, 2021

U.S. Government & Politics Twenty years later, how Americans assess the effects of the 9/11 attacks

William A. Galston

September 9, 2021

Surrounded by members of Congress, U.S. President Bush George W. Bush(at podium) prepares to sign the Homeland Security Act November 25,2002 creating a vast Department of Homeland Security to preventterrorist attacks on the United States, setting in motion the biggestgovernment reorganization in half a century that could take years tocomplete. "The continuing threat of terrorism, the threat of massmurder on our own soil will be met by a unified, effective response,"Bush said at the White House signing ceremony. REUTERS/Win McNameeWM/GAC

U.S. Government & Politics DHS twenty years after 9/11: Looking back and looking ahead

Joseph I. Lieberman

September 8, 2021

210120 Sunrise over the United States Capitol Building ahead of the 2021 U.S. Presidential Inauguration on January 20, 2021 in Washington, DC, USA. Photo: Joel Marklund / BILDBYRÅN / kod JM / JM0063 No Use Sweden. No Use Norway. No Use Austria.

U.S. Government & Politics How America’s response to 9/11 contributed to our national decline

William A. Galston

August 27, 2021

The American Flag flies at the U.S. Capitol in Washington, U.S., December 17, 2020. REUTERS/Tom Brenner

U.S. Government & Politics 20 years later: The lasting impact of 9/11 on Congress

Sarah A. Binder, Molly E. Reynolds

August 27, 2021

U.S. President George W. Bush (R) speaks during a signing ceremony tocreate the Department of Homeland Security in Washington, November 25,2002. White House advisor Tom Ridge (L), Asa Hutchinson (2nd L), thehead of the Drug Enforcement Administration and Navy Secretary GordonEngland (3rd L) listen to the President. Bush picked Ridge to be thedepartment's first secretary and said he would nominate England to bethe deputy secretary and Hutchinson to be undersecretary of border andtransportation security. REUTERS/Gary HershornGMH/ME

U.S. Government & Politics 9/11 and the reinvention of the US intelligence community

Elaine Kamarck

August 27, 2021

A U.S. and a British soldier with the NATO-led International Security Assistance Force (ISAF) stand guard during the graduation ceremony of an Afghan National Army (ANA) commando in the Rishkhur district on the outskirts of Kabul, October 10, 2007. REUTERS/Omar Sobhani (AFGHANISTAN)

Afghanistan It wasn’t hubris that drove America into Afghanistan. It was fear.

Robert Kagan

August 26, 2021

Protesters hold up their mobile phones during a demonstration in support of the EU integration at Independence Square in Kiev November 28, 2013. The European Union told Ukraine it was risking its economic future by rejecting a free-trade deal in favour of closer ties with Russia, hours before a likely frosty encounter on Thursday evening between EU leaders and President Viktor Yanukovich. REUTERS/Stoyan Nenov

Media & Journalism Journalism after 9/11

Marvin Kalb

August 25, 2021

U.S. Vice President Dick Cheney (R) speaks to President George W. Bushby phone inside the operations center at the White House with staff,September 11, 2001, the day of the terror attacks in New York andWashington. Bush on September 16, 2001 asked "horrified" Americans togo back to work this week, cautioning them to be alert for more attacksand to brace for a long crusade to "rid the world of evildoers".Picture released by the White House on September 16. REUTERS/WHITEHOUSE photo by David BohrerME

Terrorism & Extremism September 11 in the White House

Bruce Riedel

August 23, 2021

Past Event

September 25

2020

U.S. Defense Policy The needs of America’s post-9/11 veterans

Online Only

Friday, 2:00 pm - 3:15 pm EDT

A man pauses by the National Sept. 11 Memorial in New York City. (Flickr/Sarah Le Clerc, https://flic.kr/p/dPcJkN; CC BY-ND 2.0, https://creativecommons.org/licenses/by-nd/2.0/)

Defense & Security The 9/11 Commission Report, the Pandemic and the Future of Homeland Security

Carrie Cordero

September 11, 2020

U.S. President George W. Bush (C) signs H.R. 1, Implementing Recommendations of the 9/11 Commission Act of 2007, in the Oval Office of the White House in Washington, August 3, 2007. Looking on are (L-R) Homeland Security Advisor Fran Townsend, Homeland Security Secretary Michael Chertoff, Congressman Peter King (R-NY), Congressman Bernie Thompson (D-MS), Senator Joe Lieberman (I-CT), Senator Susan Collins (D-ME) and Senator Ted Stevens (R-AK). REUTERS/Jason Reed (UNITED STATES)

U.S. Government & Politics What the 9/11 Commission report had to say about Congressional oversight

Carrie Cordero

September 11, 2018

U.S. soldiers from D Troop of the 3rd Cavalry Regiment walk on hill after finishing with a training exercise near forward operating base Gamberi in the Laghman province of Afghanistan

U.S. Foreign Policy Why war powers need an expiration date

Scott R. Anderson

May 24, 2018

Past Event

September 08

2011

Terrorism & Extremism Meet the Press at Brookings: The Impact of 9/11 Ten Years On

The Brookings Institution, Washington DC

Thursday, 10:00 am - 12:00 pm EDT

Security

Drone operators fly an MQ-9 Reaper training mission from a ground control station at Holloman Air Force Base, New Mexico, in this U.S. Air Force handout photo taken October 3, 2012. Here in the New Mexico desert, the U.S. Air Force has ramped up training of drone operators - even as the nation increasingly debates their use and U.S. forces prepare to leave Afghanistan. ATTENTION EDITORS - SCREENS BLURRED AT SOURCE. To match feature USA-SECURITY/DRONES REUTERS/Airman 1st Class Michael Shoemaker/USAF/Handout (UNITED STATES - Tags: MILITARY) FOR EDITORIAL USE ONLY. NOT FOR SALE FOR MARKETING OR ADVERTISING CAMPAIGNS. THIS IMAGE HAS BEEN SUPPLIED BY A THIRD PARTY. IT IS DISTRIBUTED, EXACTLY AS RECEIVED BY REUTERS, AS A SERVICE TO CLIENTS

Terrorism & Extremism Why there hasn’t been another 9/11

Daniel L. Byman

September 11, 2021

New section of the border wall is pictured next to an older piece of fencing after U.S. President Joe Biden signed an executive order halting construction of the U.S.-Mexico border wall, in Sunland Park, New Mexico U.S., January 22, 2021. REUTERS/Paul Ratje

Mexico 9-11 and the US-Mexico border: New challenges 20 years later

Vanda Felbab-Brown

September 10, 2021

The U.S. Air Force has conducted the first flight test of an artificial intelligence “brain” system named Skyborg. The campaign is one step closer to developing unmanned “loyal wingman” drones, or remotely crewed aerial vehicles that can fly alongside jet fighters, bombers, and support aircraft. The Skyborg leadership team conducted a 2 hour and 10 minute flight test of the Skyborg autonomy core system, or ACS, aboard a Kratos UTAP-22 tactical unmanned vehicle at Tyndall Air Force Base, Florida, April 29. The USAF say: “The aim of the Skyborg Vanguard program is to integrate full-mission autonomy with low-cost, attritable unmanned air vehicle technology to enable manned-unmanned teaming. Skyborg will provide the foundation on which the Air Force can build an airborne autonomous ‘best of breed’ system of systems that adapts, orients and decides at machine speed for a wide variety of increasingly complex mission sets.” Where: Florida, United Kingdom When: 29 Apr 2021 Credit: USAF/Cover-Images.com

International Affairs “War is interested in you”: Balancing the promise and peril of high-tech deterrence

Melanie W. Sisson

September 10, 2021

A general view of Tel Aviv's skyline is seen through a hotel window in Tel Aviv, Israel May 15, 2017. Picture taken May 15, 2017. REUTERS/Amir Cohen

Terrorism & Extremism The Tel Aviv plot

Bruce Riedel

September 8, 2021

French soldiers of the "Belleface" Desert Tactical Group (GTD) conduct an area control operation in the Gourma region during the Operation Barkhane in Ndaki, Mali, July 27, 2019. Picture taken July 27, 2019. REUTERS/Benoit Tessier

Terrorism & Extremism 20 years after 9/11, jihadi terrorism rises in Africa

Alexandre Marc

August 30, 2021

U.S. President Joe Biden tours the National Counterterrorism Center Watch Floor during a visit to the Office of the Director of National Intelligence in nearby McLean, Virginia outside Washington, U.S., July 27, 2021. REUTERS/Evelyn Hockstein

Afghanistan The good enough doctrine: Learning to live with terrorism

Daniel L. Byman

August 24, 2021

FILE PHOTO: U.S. Army soldiers from the 2nd Platoon, B battery 2-8 field artillery, fire a howitzer artillery piece at Seprwan Ghar forward fire base in Panjwai district, Kandahar province southern Afghanistan, June 12, 2011. REUTERS/Baz Ratner

Terrorism & Extremism The war on terror has not yet failed: A net assessment after 20 years

Michael E. O’Hanlon, Hal Brands

July 27, 2021

FILE PHOTO: Anti-Taliban Afghan fighters watch several explosions from U.S. bombings in the Tora Bora mountains in Afghanistan in the hunt for al Qaeda fighters, December 16, 2001./File Photo

Terrorism & Extremism America failed its way to counterterrorism success

Michael E. O’Hanlon, Hal Brands

August 12, 2021

Students wear protective masks as they attend a class at school as the outbreak of the coronavirus disease (COVID-19) continues, in Peshawar, Pakistan November 23, 2020. REUTERS/Fayaz Aziz

Terrorism & Extremism A global effort to counter extremism through education

Madiha Afzal

January 25, 2021

A person has a nasal swab applied for the coronavirus disease (COVID-19) test taken at a mobile testing site in Times Square in New York City, U.S., August 16, 2021. REUTERS/Jeenah Moon

Privacy Security, privacy and the Coronavirus: Lessons from 9/11

Peter Swire

March 24, 2020

Supporters of al-Qaeda leader Osama bin Laden shout anti-American slogans, after the news of his death, during a rally in Quetta May 2, 2011. Bin Laden was killed in a U.S. helicopter raid on a mansion near the Pakistani capital Islamabad early on Monday, officials said, ending a nearly 10-year worldwide hunt for the mastermind of the Sept. 11 attacks. U.S. officials said bin Laden was found in the million-dollar compound in the military garrison town of Abbottabad, 60 km (35 miles) north of Islamabad. REUTERS/Naseer Ahmed (PAKISTAN - Tags: CIVIL UNREST CRIME LAW IMAGES OF THE DAY) - GM1E75300AX01

Terrorism & Extremism Al-Qaida today, 18 years after 9/11

Bruce Riedel

September 10, 2019

A New York City Police Department (NYPD) officer pauses at the edge of the reflecting pool at the National 9/11 Memorial and Museum during ceremonies marking the 16th anniversary of the attacks in New York, U.S., September 11, 2017. REUTERS/Brendan McDermid TPX IMAGES OF THE DAY - RC191F4FEB50

Terrorism & Extremism Have US counterterrorism efforts improved since 9/11?

Daniel L. Byman

September 10, 2018

U.S. Army soldiers from Bravo Company, 2nd Battalion, 35th Infantry Division, Task Force Cacti take part in a military re-enlistment ceremony at Forward Operating Base Joyce in Kunar province, eastern Afghanistan March 13, 2012. REUTERS/Erik De Castro (AFGHANISTAN - Tags: POLITICS MILITARY CIVIL UNREST) - GM1E83D19GV01

U.S. Defense Policy 17 years after 9/11, what it means to have Generation Z military

Brendan R. Stickles

September 10, 2018

Terrorism & Extremism On terrorists’ shift in tactics since 9/11

Chris Meserole

September 11, 2017

Terrorism & Extremism Protecting U.S. Citizens’ Constitutional Rights During the War on Terror

Benjamin Wittes

May 22, 2013

Global affairs

U.S. President George W. Bush answers questions from the press aboutIraq with Vice President Richard Cheney (L) looking on, during ameeting with Congressional leaders at the White House, September 18,2002. The president said Saddam Hussein "won't fool anybody" with hispromise to admit weapons inspectors into his country. REUTERS/LarryDowningLSD/HB

Iraq 9/11 and Iraq: The making of a tragedy

Bruce Riedel

September 17, 2021

U.S. President George W. Bush (R) stands with Mexican President VicenteFox as they address the media in the Rose Garden at the White House,October 4, 2001. Fox came to the White House to show support for theUnited States response to the attacks in New York and Washington.REUTERS/Gary HershornGMH/ME

North America 9/11 transformed US-Mexico relations

Arturo Sarukhan

September 17, 2021

U.S. Air Force pararescuemen secure an area in Afghanistan, Nov. 7, 2012, (https://www.dvidshub.net/image/791522/pararescue-afghanistan/Staff Sgt. Jonathan Snyder/United States Air Force)

Afghanistan Remembering the gains of the Afghanistan war

Benjamin Wittes, Daniel L. Byman

September 10, 2021

U.S. Foreign Policy September 11 and America’s response through the eyes of Nelson Mandela

Shibley Telhami

September 9, 2021

U.S. President George W. Bush rides with Russian President Vladimir Putin in the front of his pickup truck as he welcomes Putin to his ranch in Crawford, Texas November 14, 2001. [Bush plans to treat Putin to Western-style entertainment and tour of his beloved ranch, as well as follow up on their talks in Washington on Tuesday on a new strategic relationship. ] Win McNamee / Reuters.

Terrorism & Extremism The impact of September 11 on US-Russian relations

Angela Stent

September 8, 2021

Protesters stand atop a vehicle during demonstrations in Cairo January 29, 2011. Thousands of angry Egyptians rallied in central Cairo on Saturday to demand that President Hosni Mubarak resign, dismissing his offer of dialogue and calling on troops to come over to their side. REUTERS/Asmaa Waguih (EGYPT - Tags: CIVIL UNREST POLITICS)

Terrorism & Extremism Sound and fury in the post-9/11 Middle East

Shadi Hamid

September 8, 2021

File photo dated March 25, 2003 of United States President George W. Bush (R) speaks next to US Secretary of Defense Donald Rumsfeld (C) and US Deputy Secretary of Defense Paul Wolfowitz (L) during a visit at the Pentagon in Arlington, Virginia. Donald Rumsfeld, the acerbic architect of the Iraq war and a master Washington power player who served as US secretary of defense for two presidents, has died at the age of 88. Photo by Alex Wong/Pool via CNP/ABACAPRESS.COM

U.S. Foreign Policy Reflections on the long-term repercussions of September 11 for US policy in the Middle East

Itamar Rabinovich

September 7, 2021

Afghan citizens, who have been evacuated from Kabul, arrive at Naval Station (NAVSTA) Rota Air Base in Rota, southern Spain, August 31, 2021. REUTERS/Jon Nazca

Afghanistan The war in Afghanistan has shaped an entire generation in the West

Constanze Stelzenmüller

September 2, 2021

A military helicopter lands at Camp Nathan Smith in Kandahar City, Kandahar Province, Afghanistan.

Afghanistan Why did state-building efforts in Afghanistan fail?

Jennifer Brick Murtazashvili, David Dollar

August 30, 2021

The flag of the Islamic Emirate of Afghanistan (Taliban) is pictured from the Dowqarun border crossing between Iran and Afghanistan, Razavi Khorasan Province, Iran August 29, 2021. Majid Asgaripour/WANA (West Asia News Agency) via REUTERS

Afghanistan Will the Taliban regime survive?

Vanda Felbab-Brown

August 31, 2021

Technology & Information How technology and the world have changed since 9/11

Darrell M. West, Nicol Turner Lee

August 27, 2021

KHATLON REGION, TAJIKISTAN, AUGUST 10, 2021: A joint military exercise by Russia, Tajikistan and Uzbekistan on the Harb-Maidon military training ground, at 20 km from the border to Afghanistan. 2,500 servicemen (including 1,800 Russian servicemen) with around 500 pieces of military hardware are taking part in the military exercise, which runs from 5 to 10 August 2021. Nozim Kalandarov/TASS.

Central Asia Russia and America’s overlapping legacies in Afghanistan

Pavel K. Baev

August 18, 2021

FILE PHOTO: A Taliban fighter holding an M16 assault rifle stands outside the Interior Ministry in Kabul, Afghanistan, August 16, 2021.REUTERS/Stringer/File Photo

Afghanistan Why the Taliban won, and what Washington can do about it now

Vanda Felbab-Brown

August 17, 2021

A member of Taliban (C) stands outside Hamid Karzai International Airport in Kabul, Afghanistan, August 16, 2021. REUTERS/Stringer

Afghanistan Around the halls: The Taliban retakes Afghanistan

Madiha Afzal, Ranj Alaaldin, Daniel L. Byman, Giovanna De Maio, Vanda Felbab-Brown, Marvin Kalb, Suzanne Maloney, Patrick W. Quirk, Itamar Rabinovich, Douglas A. Rediker, Bruce Riedel, Federica Saini Fasanotti, Constanze Stelzenmüller, Shibley Telhami

August 16, 2021