Jonathan Valdez explores the role of ideology in the maintenance and subsequent collapse of Soviet influence in Eastern Europe. He looks at how Marxism-Leninism was used to legitimize Soviet influence in Eastern Europe, to rationalize policy decisions, to communicate Soviet intent and policy desires to East European elites, and to explain change in socialist systems. The author argues that the use of the fundamental principles of Marxism-Leninism to perform various functions ultimately brought about a change in the basic assumptions of the theory itself.