Legal Constraints on the FBI and “the Wall” The FBI had different tools for law enforcement and intelligence. For criminal matters, it could apply for and use traditional criminal warrants. For intelligence matters involving international terrorism, however, the rules were different. For many years the attorney general could authorize surveillance of foreign powers and agents of foreign powers without any court review, but in 1978 Congress passed the Foreign Intelligence Surveillance Act. This law regulated intelligence collection directed at foreign powers and agents of foreign powers in the United States. In addition to requiring court review of proposed surveillance (and...