Counterterrorism and Homeland Security

Insurgents and violent extremists pose a constantly evolving threat, both in the United States and globally. CSIS research provides strategic thinking on the range of efforts to counter terrorist groups and their methods across the world.

Photo: AFP/Getty Images

Photo: AFP/Getty Images

Why Did Pakistan Announce “Open War” Against the Taliban?

Early in the morning of February 27, Pakistan’s defense minister announced “open war” between Pakistan and the Taliban, a group that Islamabad frequently backed in its 30-year quest to rule Afghanistan.

Critical Questions by Alexander Palmer and Alexander Margolis — February 27, 2026

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Seth G. Jones

Seth G. Jones

President, Defense and Security Department; Harold Brown Chair
Daniel Byman

Daniel Byman

Director, Warfare, Irregular Threats, and Terrorism Program
Riley McCabe

Riley McCabe

Associate Fellow, Warfare, Irregular Threats, and Terrorism Program

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Why Did Pakistan Announce “Open War” Against the Taliban?

Early in the morning of February 27, Pakistan’s defense minister announced “open war” between Pakistan and the Taliban, a group that Islamabad frequently backed in its 30-year quest to rule Afghanistan.

Critical Questions by Alexander Palmer and Alexander Margolis — February 27, 2026

What Is Next After the Suicide Attack in Pakistan?

This morning, a suicide bomber attacked a Shia mosque in Islamabad, Pakistan. The most likely perpetrator is the Islamic State–Khorasan Province, which operates both in Afghanistan and Pakistan but has a significant interest in mass-casualty international attacks. 

Critical Questions by Alexander Palmer and Alexander Margolis — February 6, 2026

Why Did the United States Conduct Strikes in Nigeria?

Isolated strikes like the ones carried out by the United States are unlikely to significantly reduce the terrorist threat in the region or reverse Nigeria’s growing insecurity.

Critical Questions by Alexander Palmer and Erin Oppel — December 26, 2025

Ideological Trends in U.S. Terrorism

The Warfare, Irregular Threats, and Terrorism Program examines the state of terrorism in the U.S., finding left-wing violence has risen in the last decade but from very low levels and still well below historic levels of violence by right-wing and jihadist actors.

Analysis by Daniel Byman and Riley McCabe — September 26, 2025

Global Terrorism Threat Assessment 2025

Terrorism remains a threat to U.S. citizens, assets, and interests despite the national security community’s decreasing focus on counterterrorism.

Report by Alexander Palmer, Riley McCabe, Daniel Byman, and Skyeler Jackson — March 28, 2025