How do the Central Intelligence Agency and the Federal Bureau of Investigation divide counterintelligence responsibilities?

The Central Intelligence Agency (CIA) and the Federal Bureau of Investigation (FBI) maintain distinct but cooperative roles in U.S. counterintelligence efforts.

• FBI Responsibility: The FBI is the principal federal agency responsible for domestic counterintelligence. It operates under the Department of Justice and is tasked with correlating and disseminating intelligence related to domestic security to other federal agencies.12
• CIA Responsibility: The CIA serves as the principal foreign intelligence and counterintelligence agency of the U.S. government. Its mandate focuses on collecting and evaluating foreign intelligence and advising the National Security Council on national security matters.32

While their primary jurisdictions are divided between domestic and foreign spheres, the two agencies cooperate extensively on counterintelligence, counterterrorism, and efforts to combat international crime. Following the September 11 attacks, this integration deepened, with CIA officers assigned to FBI units and FBI agents working at CIA headquarters to improve coordination. Other entities, such as the Department of Defense and various military intelligence services, also perform counterintelligence functions within their specific jurisdictions.2