The emphasis of this paper is on the effect of the state claiming a privilege of national security in a criminal case, either to: (1) prevent the defendant from gaining discovery of classified information which could be important in defending against the criminal charges; or (2) prevent the defendant from introducing classified evidence in his/her own defense, access to which has usually been gained by virtue of the defendant’s own activity with the intelligence services (CIA, FBI) or other police agencies. The state often claims national security in situations where the state itself is either dealing with criminals or using criminal methods in conducting normal criminal investigations, or, as in cases under the Classified Information Procedures Act, in conducting foreign or domestic policy.
Thaman, Stephen C., Official Privilege: State Security and the Right to a Fair Trial in the USA (2002). National Security and International Criminal Justice. (Kluwer) (H. Roggemann & P. Sarcevic eds. 2002).