Soviet Penetration of the United States

With the collapse of the Soviet Union, the world was able to gain at least partial access to archives that confirm some of the worst estimations of Soviet oppression at home and meddling abroad. When FDR established diplomatic relations with Moscow, in 1933, it marked the beginning of decades of extensive Soviet penetration of the United States, through front organizations, agents of influence, and outright spies. This is now well catalogued in many outstanding books listed here.