---
title: "War on Terrorism — APUSH Definition & Exam Guide"
description: "The war on terrorism was the U.S. military and security campaign launched after 9/11. Learn how APUSH tests it, from civil liberties debates to Period 9 causation."
canonical: "https://fiveable.me/apush/key-terms/war-on-terrorism"
type: "key-term"
subject: "AP US History"
unit: "Unit 9"
---

# War on Terrorism — APUSH Definition & Exam Guide

## Definition

The war on terrorism is the U.S. military and security campaign launched after the September 11, 2001 attacks, which led to lengthy, controversial conflicts in Afghanistan and Iraq and raised major questions about civil liberties and human rights (KC-9.3.II.A and KC-9.3.II.B).

## What It Is

The war on terrorism is the umbrella name for everything the United States did after the [September 11, 2001 attacks](/apush/key-terms/september-11-2001-attacks "fv-autolink") on the [World Trade Center](/apush/unit-9/challenges-21st-century/study-guide/EXLLVyYPLInl4kY1shVW "fv-autolink") and the Pentagon to fight terrorist threats. Abroad, that meant military campaigns against terrorism, including the long and controversial wars in Afghanistan (starting 2001, targeting Al-Qaeda and the Taliban) and Iraq (starting 2003). At home, it meant a major push to improve domestic security through new surveillance powers, airport screening, and agencies like the Department of Homeland Security.

Here's the tension the CED wants you to see. The same policies that sought to make Americans safer also raised hard questions about civil liberties and human rights. Think expanded government surveillance, detention of suspects without trial at Guantanamo Bay, and debates over interrogation methods. The war on terrorism is not just a foreign policy story. It's a story about how far a democracy will trade liberty for security, which is a theme [APUSH](/apush "fv-autolink") has been building since World War I.

## Why It Matters

This term sits in Topic 9.6 (Challenges of the 21st Century) in [Unit 9](/apush/unit-9 "fv-autolink"): Globalization and Contemporary America, 1980-Present. It directly supports learning objective APUSH 9.6.A, explaining the causes and effects of the domestic and international challenges the U.S. faced in the 21st century. The essential knowledge is unusually specific here. KC-9.3.II.A covers the post-9/11 military efforts and the Afghanistan and Iraq conflicts, and KC-9.3.II.B covers the security-versus-civil-liberties tradeoff. The term also feeds [Topic 9.7](/apush/unit-9/causation-period-9/study-guide/9F58jAjqrlXeUuHFNrtT "fv-autolink") (Causation in Period 9) and APUSH 9.7.A, because the war on terrorism is one of the biggest changes shaping American national identity after 1980. For the exam, it's a go-to example for the American and National Identity theme and the America in the World theme, and it's one of the most recent events you can legally use as evidence.

## Connections

### [9/11 Terrorist Attacks (Unit 9)](/apush/key-terms/911-terrorist-attacks)

9/11 is the cause; the war on terrorism is the effect. The attacks on the World Trade Center and Pentagon triggered the entire campaign, so any causation question about 21st-century [foreign policy](/apush/key-terms/foreign-policy "fv-autolink") starts here.

### [Al-Qaeda (Unit 9)](/apush/key-terms/al-qaeda)

[Al-Qaeda](/apush/key-terms/al-qaeda "fv-autolink") carried out the 9/11 attacks and was the original target of the war on terrorism. The invasion of Afghanistan happened because the Taliban government sheltered Al-Qaeda there.

### Wartime Civil Liberties: Espionage Act and Japanese Internment (Unit 7)

The [civil liberties](/apush/key-terms/civil-liberties "fv-autolink") debate after 9/11 is a rerun of an old APUSH pattern. The Espionage and Sedition Acts in WWI and Japanese internment in WWII show the same move, where national security crises lead the government to restrict individual rights. This is gold for continuity-over-time essays.

### Cold War Foreign Policy (Unit 8)

The war on terrorism replaced containment of communism as the organizing principle of U.S. foreign policy. Both involved long, open-ended global commitments, controversial wars (Vietnam, Iraq), and domestic fears that strained civil liberties (the Red Scare parallels post-9/11 surveillance debates).

## On the AP Exam

Multiple-choice questions test whether you know the goal of the war on terrorism (combating terrorist threats and improving domestic security), can identify specific actions taken as part of it (the wars in Afghanistan and Iraq, expanded surveillance), and can name a civil liberty that became controversial during it (privacy and protection from government surveillance is the classic answer). No released FRQ has used this term verbatim, but it's strong evidence for short-answer and essay prompts about Period 9 change, continuity in wartime civil liberties restrictions, or shifts in American national identity after 1980. The key skill is causation. Be ready to argue 9/11 caused the war on terrorism, which in turn caused the Afghanistan and Iraq conflicts and the security-versus-liberty debate.

## war on terrorism vs The Iraq War

The war on terrorism is the broad, ongoing campaign against terrorist threats worldwide. The Iraq War (2003) was one specific conflict launched under that umbrella, and a controversial one, since Iraq had no direct role in 9/11 and the claimed weapons of mass destruction were never found. The Afghanistan war was the direct response to 9/11; Iraq was the more contested extension. On MCQs, don't treat 'war on terrorism' and 'Iraq War' as interchangeable.

## Key Takeaways

- The war on terrorism was the U.S. military and security campaign launched after the 9/11 attacks on the World Trade Center and Pentagon in 2001.
- It produced two lengthy, controversial conflicts, the war in Afghanistan starting in 2001 and the war in Iraq starting in 2003 (KC-9.3.II.A).
- The campaign sought to improve security inside the United States but raised serious questions about civil liberties and human rights (KC-9.3.II.B).
- It fits a long APUSH pattern where wartime security fears lead to restrictions on rights, just like the Espionage Act in WWI and Japanese internment in WWII.
- For Topic 9.7 causation questions, treat 9/11 as the cause, the war on terrorism as the immediate effect, and the civil liberties debate as a longer-term effect on national identity.

## FAQs

### What was the war on terrorism in APUSH?

It was the U.S. military and security campaign launched after the September 11, 2001 attacks, including the wars in Afghanistan and Iraq plus expanded domestic security measures. The CED covers it in Topic 9.6 under KC-9.3.II.A and KC-9.3.II.B.

### Did the war on terrorism only happen overseas?

No. Alongside the wars in Afghanistan and Iraq, it included a major domestic side, like expanded government surveillance and new security agencies. That domestic side is exactly what sparked the civil liberties controversies the CED highlights.

### How is the war on terrorism different from the Iraq War?

The war on terrorism is the entire campaign against terrorist threats after 9/11; the Iraq War (2003) was one specific conflict within it. Afghanistan was the direct response to 9/11, while Iraq was a more controversial extension of the broader campaign.

### Why was the war on terrorism controversial?

Two main reasons. The Iraq conflict was long and contested, and domestic security measures like expanded surveillance raised questions about protecting civil liberties and human rights. The CED frames it as a security-versus-liberty tradeoff.

### Is the war on terrorism on the AP exam?

Yes. It's named in the Period 9 essential knowledge (KC-9.3.II.A and B), shows up in multiple-choice questions about 21st-century challenges, and works as evidence in essays about causation, national identity, or continuity in wartime civil liberties restrictions.

## Related Study Guides

- [9.7 Causation in Period 9](/apush/unit-9/causation-period-9/study-guide/9F58jAjqrlXeUuHFNrtT)

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