War on terror

The war on terror was a big, global military effort started by the United States after the September 11 attacks in 2001. It was officially called the Global War on Terrorism and aimed to stop groups that use violence against innocent people. The main focus was on stopping groups like al-Qaeda and the Taliban, as well as stopping other dangerous groups and leaders who supported such actions.

This effort led to many military actions in different places, such as Afghanistan, Iraq, and other countries. It changed how countries worked together to keep people safe and brought up many questions about right and wrong ways to fight danger. Over time, people had different opinions about whether these actions helped or hurt the world.

Today, the ideas from this time still shape how countries try to protect their people and work together to prevent violence. It showed how important it is to think carefully about how we keep people safe while also respecting everyone's rights.

Etymology

The phrase war on terror was used to describe a big military effort led by the United States, the United Kingdom, and some other countries. They were fighting against groups and leaders they called terrorists. This wasn’t the only name for the fight—it was also called "World War III", "World War IV", "Bush’s War on Terror", "The Long War", "The Forever War", "The Global War on Terror", "The War Against al-Qaeda", or "The War of Terror".

Before the attacks on September 11, 2001, people sometimes talked about fighting terrorism, but after that day, the phrase became very well-known. Leaders said this was a big fight that would take time. Over the years, some leaders stopped using the phrase "war on terror" and instead talked about working against specific groups that threaten safety. Even so, the idea of fighting against these groups continued in different forms.

Background

In the late 1990s, a group led by Osama bin Laden began planning attacks against the United States from Afghanistan. In Afghanistan, a strict government called the Taliban was in control. Bin Laden called for war against the United States.

These plans led to several attacks. This included bombings of U.S. embassies in Kenya and Tanzania in 1998, and an attack on a U.S. ship in Yemen in 2000. The most tragic was the attacks on September 11, 2001. On that day, nineteen men took control of four airplanes. They crashed two into buildings in New York City, one into a building in Virginia, and the fourth into a field in Pennsylvania. Many people were hurt or lost their lives that day.

Main article: September 11 attacks

American objectives

The Authorization for Use of Military Force Against Terrorists became law in September 2001. It let the United States use its military against groups or countries linked to the September 11 attacks. The law gave the president power to act against anyone who helped plan, support, or do these attacks.

The goals were to stop harmful groups, stop countries from supporting them, reduce problems that might lead to such actions, and protect American people and interests at home and around the world. The law allowed military actions in many countries, sometimes without full public details.

Timeline

For a chronological guide, see timeline of the War on Terror.

The War on Terror began after attacks in 2001. After this, the United States started a global effort to stop harmful groups. This effort focused on stopping groups that used violence. It was a big change from earlier times when the world was mostly focused on other kinds of conflict.

Operation Enduring Freedom

Main article: Operation Enduring Freedom

Operation Enduring Freedom was a big military effort started by the United States after the attacks on September 11, 2001. This effort fought against groups that use violence, especially a group called al-Qaeda and their allies. At first, it was called "Eternal Justice," but the name was changed to "Enduring Freedom" because it upset many people.

Afghanistan

Main article: War in Afghanistan (2001–2021)

After the September 11 attacks, the United States asked Afghanistan's leaders to hand over important members of al-Qaeda or face attacks. When they refused, the United States and its friends started a military operation in Afghanistan. It began with airplanes bombing places where these groups hid. Later, soldiers went into the country to fight against them. The fighting continued in many parts of Afghanistan as these groups tried to return.

In 2014, Afghanistan and the United States agreed that American and NATO soldiers could stay to help until at least 2024. But in 2020, the United States made a deal to start bringing soldiers home. By 2021, most soldiers had left, and Afghanistan's leaders took control again.

International Security Assistance Force

Main article: International Security Assistance Force

After the fighting began, a group called the International Security Assistance Force was created to help the new government in Afghanistan. This group included soldiers from many countries working together to support peace and order.

Philippines

Main article: Operation Enduring Freedom – Philippines

In 2002, the United States sent soldiers to the Philippines to help local forces fight against harmful groups. They also worked on projects to help people, like giving medical care, to earn the trust and support of local communities.

Trans-Sahara (Northern Africa)

Main article: Operation Juniper Shield

US Secretary of Defense Donald Rumsfeld with Chairman of the Joint Chiefs of Staff General Richard B. Myers and joined by military representatives from 29 countries of the worldwide coalition on the war against terrorism, at The Pentagon, 11 March 2002

The United States and its partners worked in parts of Africa to stop harmful groups and to prevent the illegal trade of weapons and drugs. This included helping countries like Mali when they asked for support against groups trying to control parts of their land.

Horn of Africa and the Red Sea

Main article: Operation Enduring Freedom – Horn of Africa

Further information: Ethiopian occupation of Somalia (2006–2009), Somali Civil War (2009–present), American military intervention in Somalia (2007–present), and CIA activities in Somalia

The United States also worked in the Horn of Africa to stop harmful activities and to train local soldiers. This included helping countries like Djibouti, Kenya, and Ethiopia. The effort also involved giving aid, like building schools and clinics, to support the communities where they worked.

Military operations by country

Iraq War

Main article: Iraq War

Further information: Iraq War and the war on terror

2002 State of the Union Address

Main article: Axis of evil

In 2002, a leader of the United States spoke about three countries — North Korea, Iran, and Iraq — saying they were helping dangerous groups and trying to make weapons that could harm many people. These countries were called the "Axis of evil".

Prelude

Further information: Preparations for 2003 invasion of Iraq and Saddam–al-Qaeda conspiracy theory

In 2002, the United States asked to use military force against Iraq. In early 2003, a leader spoke at the United Nations, saying Iraq had secret weapons and connections with a group called Al-Qaeda.

Invasion of Iraq

Main article: 2003 invasion of Iraq

The Iraq War began in March 2003 with airplanes and soldiers from the United States and its friends. They said Iraq had weapons that could harm many people, but later this was found to be wrong. Iraq had been listed as helping dangerous groups since 1990. The fighting began with a battle at a port town, and soon the capital, Baghdad, was taken over. By May 2003, the main fighting stopped.

Iraqi Insurgency (2003–11)

Main article: Iraqi Insurgency

After the fighting stopped, some people in Iraq started fighting back against the United States and the new government. These fighters included members who used to work for the old leader, Saddam Hussein, and others who wanted to create an old Islamic state. Saddam Hussein was caught in 2003 and removed from power in 2006.

In 2007, a new plan was tried that helped lower fighting in Iraq. The United States stopped most big fighting there in 2010.

War in Iraq (2013–17)

Main article: War in Iraq (2013–2017)

After most United States soldiers left in 2011, some came back in 2014 to help fight a group called the Islamic State. As of July 2021, about 2,500 United States soldiers were still in Iraq, helping to fight this group.

Pakistan

Main articles: Pakistan in the war on terror, Insurgency in Khyber Pakhtunkhwa, and Pakistan and state-sponsored terrorism

After the attacks on September 11, 2001, the leader of Pakistan agreed to help the United States. This led to the United States using air bases in Pakistan. In 2002, the leader of Pakistan spoke out against extreme groups and arrested some leaders of these groups.

In 2004, the army of Pakistan started operations in areas where extreme groups were hiding. The United States used drone airplanes to attack these groups in Pakistan, which caused some disagreement about rules and agreements.

Yemen

Main articles: Al-Qaeda insurgency in Yemen, Drone strikes in Yemen, and Yemeni civil war (2014-present)

The United States has used military actions against extreme groups in Yemen since the war on terror began. Yemen has a weak government, and extreme groups have found places to hide and plan. The United States has given more help and money to Yemen to support efforts against these groups.

Current phase: Islamic State, Iran, and focus on narcoterrorism (2021–present)

Main articles: US intervention in the Syrian civil war § 2024–present: Post-Assad drawdown, Operation Hawkeye Strike, 2025 United States strikes in Nigeria, War on drugs § War on cartels (2025–present), and Operation Southern Spear

During the 2020s, efforts to stop harmful groups became smaller and less intense after big wars in Iraq and Afghanistan ended. The United States and its partners now use smarter ways to protect people, like sharing information and working together with friends. In 2022, a leader of a harmful group was removed by a drone.

Today, there are still operations in places like Somalia and Yemen. Some groups still cause trouble by using the internet to share messages and plan activities. In 2025, the United States took steps to stop groups linked to illegal activities in Latin America. These actions show how ways to protect people are changing, with more focus on working together and using different methods to keep everyone safe.

Other military operations

Operation Inherent Resolve (Syria and Iraq)

Main articles: Operation Inherent Resolve, Military intervention against ISIL, and List of wars and battles involving ISIL

Further information: American-led intervention in Iraq (2014–2021), Spillover of the Syrian Civil War, and American-led intervention in Syria

In 2014, the United States began using airstrikes to fight a group called the Islamic State in Iraq and Syria. The goal was to weaken and defeat this group. More troops were sent to help local forces, and attacks continued in both Iraq and Syria.

Islamic State of Lanao and the Battle of Marawi

With the rise of the Islamic State in Iraq and Syria, smaller groups inspired by them appeared in other parts of the world, including the Philippines. One such group attacked the city of Marawi in 2017, leading to a long and difficult battle.

Libyan War

Main articles: Factional violence in Libya (2011–2014), Libyan Civil War (2014–2020), and American intervention in Libya (2015–2019)

The Islamic State also tried to gain control in Libya, taking over parts of the country. Local forces, with help from airstrikes, fought back and pushed them out of their main city, Sirte.

An AV-8B Harrier takes off from the flight deck of USS Wasp during Operation Odyssey Lightning, 8 August 2016.

American military intervention in Cameroon

In 2015, the United States sent soldiers to Cameroon to help local forces fight the Islamic State. Their role was to support and provide information, not to fight directly.

Operation Active Endeavour

Main article: Operation Active Endeavour

After the attacks on September 11, 2001, NATO began a naval operation called Active Endeavour. Its purpose was to keep the seas safe by stopping any movement of harmful groups or weapons.

Political map: the Kashmir region districts

Fighting in Kashmir

Main article: Kashmir conflict

Some groups in Kashmir have been involved in conflicts, and there have been concerns about links to larger militant networks. There have been several incidents involving drone attacks and military operations in the region.

Anti-terror campaigns by other powers

As part of ongoing regional conflicts, countries like Israel and Saudi Arabia have taken actions against militant groups. Colombia has also focused on counter-terrorism efforts, especially during the presidency of Álvaro Uribe. In recent years, China has conducted campaigns against separatist movements in Xinjiang, and Russia has dealt with separatist and militant groups in Chechnya and during its involvement in the Syrian Civil War.

International military support

Main articles: Participants in Operation Enduring Freedom and Multi-National Force – Iraq

The invasion of Afghanistan was the first big action in this global effort. Forces from the United States, the United Kingdom, and the Afghan Northern Alliance worked together. Later, troops and aircraft from countries such as Australia, Canada, Denmark, France, Italy, the Netherlands, New Zealand, and Norway also joined in. By 2006, about 33,000 troops were in Afghanistan.

After the attacks on September 11, 2001, NATO said these attacks were an attack on all its members. Australia also promised to help. In the months that followed, NATO worked together to protect people and keep travel safe. This included naval operations in the Mediterranean Sea to stop dangerous groups and to make sure ships could travel safely.

Domestic aspects

Main article: Patriot Act

Further information: Mass surveillance in the United States and NSPM-7

After the attacks on September 11, 2001, the United States made changes to help keep people safe. New groups were created, like the United States Department of Homeland Security, to protect the country. Laws were also changed to help police and government workers stop bad actions before they happen.

Some people worried that these changes might take away some of their rights. Courts checked these worries to make sure the rules were followed.

Extrajudicial detention

After the September 11 attacks in 2001, the United States started a program called "extraordinary rendition." This meant taking people from one country to another without following normal laws. The goal was to question these individuals in places where they did not have the usual legal protections. This practice continued even after new leaders took over in the United States.

The United States also used secret prisons, known as "black sites," to hold people captured during their efforts against harmful groups. These secret prisons were not officially admitted to by the United States government. Holding people in these secret places went against international agreements that many countries had agreed to follow. Some of these secret prisons were later closed, but the actions caused problems and debates in many countries.

The United States also opened a prison at Guantanamo Bay in 2002. This prison was set up in a special area that is not part of the United States, which allowed the government to avoid some normal rules. Many people were kept there for a long time without being charged with a crime. Some were eventually sent to other countries. As of 2025, only a few people remain in this prison, with some waiting to be moved, some facing charges, and others being held without a set end date.

Main article: Guantanamo Bay detention camp

Major terrorist attacks and plots since 9/11

Following efforts to stop harmful groups after the attacks on September 11, 2001, several groups and individuals carried out attacks in many places, even where there was no fighting.

Attacks by Al-Qaeda

Main articles: al-Qaeda and Timeline of al-Qaeda attacks

The 2002 Bali bombings in Indonesia were done by members of Jemaah Islamiyah, a group linked to Al-Qaeda.
Al-Qaeda in the Islamic Maghreb said they were responsible for the 11 April 2007 Algiers bombings, targeting government offices.
Morocco said Al-Qaeda was to blame for the 2011 Marrakech bombing, though the group denied this.
No one claimed responsibility for the 2012 US Consulate attack in Benghazi in Libya. Some believe groups linked to Al-Qaeda may have been involved.
The people in the Charlie Hebdo shooting in Paris said they were part of al-Qaeda’s Al-Qaeda in the Arabian Peninsula.
Al-Qaeda in the Arabian Peninsula said they were behind the Naval Air Station Pensacola shooting in the United States.

Islamic State

Main articles: Islamic State of Iraq and the Levant and List of terrorist incidents linked to ISIL

The 2013 Reyhanlı bombings in Turkey caused injuries.
The 2014 Canadian parliament shootings were inspired by Islamic State.
The November 2015 Paris attacks caused many deaths and injuries, and Islamic State said they were responsible.
The 2015 San Bernardino attack in California killed many people.
The 2016 Brussels bombings in Belgium caused deaths and injuries.
The 2016 Orlando nightclub shooting in Florida was a very serious event.
The 2024 Crocus City Hall attack in Russia was one of the deadliest attacks in recent history.

Attacks by other Islamist militant groups and individuals

The 2003 Casablanca bombings were carried out by Salafia Jihadia.
The 2003 Istanbul bombings targeted British and Jewish sites.
The 2004 Madrid train bombings were done by people opposing Spain’s involvement in wars abroad.
The 7 July 2005 London bombings targeted London’s public transport.
The 2007 Glasgow International Airport attack was carried out by two individuals.
The 2023 7th October Attack targeted Israeli soldiers and civilians.

Alleged plots and unsuccessful attacks

There have been reports of planned attacks that did not succeed, including:

2001 threat against West Coast suspension bridges (United States)
2004 financial buildings plot (The United States and the United Kingdom)
21 July 2005 London bombings (United Kingdom)
2006 Toronto terrorism plot (Canada)
2006 transatlantic aircraft plot involving liquids on airplanes
2006 Hudson River bomb plot (United States)
2007 Fort Dix attack plot (United States)
2007 London car bombs (United Kingdom)
2007 John F. Kennedy International Airport attack plot (United States)
2009 Bronx terrorism plot (United States)
2009 New York City Subway and United Kingdom plot (The United States and the United Kingdom)
2009 Northwest Airlines Flight 253 bombing plot (United States)
2010 Stockholm bombings (Sweden)
2010 Times Square car bombing attempt (United States)
2010 cargo plane bomb plot (United States)
2010 Portland car bomb plot (United States)
2011 Manhattan terrorism plot (United States)
2013 Via Rail Canada terrorism plot (Canada)
2014 mass-beheading plot (Australia)

Casualties

The war on terror, also called the Global War on Terrorism, began after the September 11 attacks in 2001. It involved many countries working together to stop groups that used violence.

It is hard to know exactly how many people were hurt or died because the fighting happened in many places. Many people were forced to leave their homes because of the fighting. In the United States, many veterans needed help for their mental health after their time in these wars.

Costs

The war on terror lasted many years and cost a lot of money — more than people first thought. Experts say the total cost was around $8 trillion for operations from 2001 to 2022, plus another $2.2 trillion to help veterans over the next 30 years. This money was spent in places like Afghanistan, Iraq, and Syria, as well as other areas.

Every day, the government spent millions to support military operations. For example, in 2015, it was estimated that the United States spent about $9.4 million each day on efforts in Syria and Iraq. The costs kept growing over time, showing how expensive and long this conflict was.

Criticism

Main article: Criticism of the war on terror

Many people have questioned the ideas and actions behind the global effort against terrorism that began after the September 11 attacks. Some say calling it a "war" is not right because terrorism is a method used by people, not a country or group you can fight like in other wars. They worry that this way of thinking has been used to limit people’s freedoms.

Others point out that using military force in places like Iraq and Afghanistan has caused many problems, including hurting many people who were not involved in fighting. Some believe that this approach has made some countries less trusted around the world. There are also concerns that the effort has sometimes been used to control groups of people inside countries. Overall, many think the effort against terrorism has had big effects on many lives.