Encyclopedias, Almanacs, Transcripts, and Maps
- Appointing and Removal Power, Presidential
- Appointment of Supreme Court Justices
- Appointments Clause
- Aptheker v. Secretary of State 378 U.S. 500 (1959)
- Arafat, Yasser
- Archeology and Artifacts, Protection of During War
- Architecture and Structural Security
- Area 51 (Groom Lake, Nevada)
- Argentina, Intelligence and Security
- Argersinger v. Hamlin 407 U.S. 25 (1972)
- Arlington Heights v. Metropolitan Housing Development Corp. 429 U.S. 252 (1977)
- Armed Forces
- Armed Islamic Group (GIA)
- Arms Control, United States Bureau
- Army for the Liberation of Rwanda (ALIR)
- Army Security Agency
- Arnett v. Kennedy 416 U.S. 134 (1974)
- Arnold, Thurman (1891–1969)
- Arrest Warrant
- Arthur, Chester A. (1830–1886)