Counterintelligence and Combatting Terrorism
During the Spanish-American War of 1898, even though the War and Navy Departments had been expanding their foreign intelligence activities, the Secret Service was responsible for counterintelligence. The Director of Naval Intelligence is responsible for counterintelligence, law enforcement, information and physical security, investigative services, and anti-terrorism in the navy. In the air force, investigative services (for law enforcement and counterintelligence), counterintelligence, anti-terrorism, and personal protective service operations are Air Force Office of Special Investigations missions. Counterintelligence investigations are conducted using techniques similar to those employed in law enforcement, but are directed at detecting, preventing, and neutralizing actual or potential threats to security. United States Marine Corps counterintelligence doctrine is similar to army doctrine, and the marine corps counterintelligence resources repose in interrogator-translator teams and counterintelligence teams. The separate brigade's operations security support and counterintelligence teams are deployed in the area of operations for communications security purposes and to detect security violations.