What was the War on Terror?

The War on Terror was a global campaign waged by the United States and many allied nations against terrorist organizations and the governments that supported them, launched after the September 11, 2001 attacks and continuing in various forms for more than two decades. The campaign combined military operations, intelligence work, financial measures, law enforcement, and diplomacy. Its main targets were al-Qaeda, the Taliban regime that had sheltered al-Qaeda in Afghanistan, regional al-Qaeda affiliates such as al-Qaeda in the Arabian Peninsula and al-Qaeda in the Islamic Maghreb, and later the Islamic State of Iraq and Syria, which arose during the Iraq War.

The most visible elements were two major wars. Operation Enduring Freedom in Afghanistan began on October 7, 2001 and continued until the American withdrawal in August 2021, making it the longest war in American history. Operation Iraqi Freedom in Iraq began on March 19, 2003 and formally ended in December 2011, although American forces returned to Iraq in 2014 to fight the Islamic State.

The campaign also included smaller but significant operations in Pakistan, Yemen, Somalia, Libya, the Philippines, Mali, Niger, and elsewhere. Drone strikes by the CIA and the Air Force became a central tool, killing senior al-Qaeda leaders including Anwar al-Awlaki in Yemen in 2011 and Ayman al-Zawahiri in Kabul in 2022. Special Operations Forces conducted thousands of raids, the most famous being the May 2, 2011 mission by Navy SEAL Team Six that killed Osama bin Laden at his compound in Abbottabad, Pakistan.

Beyond the battlefield, the United States led international efforts to track terrorist financing, share intelligence, and tighten airline and border security. The North Atlantic Treaty Organization invoked Article 5 of its founding treaty for the first and only time on September 12, 2001, and NATO partners contributed troops to Afghanistan.

Domestically, the War on Terror created the Department of Homeland Security in November 2002, the Transportation Security Administration in 2002, and the Director of National Intelligence in 2004, and it produced major surveillance programs revealed by Edward Snowden in 2013. The total cost is estimated at more than 8 trillion dollars and over 7,000 American military deaths, plus several hundred thousand civilian deaths in Iraq and Afghanistan combined. The phrase fell out of official use during the Obama administration but the underlying counterterrorism mission continues.