The U.S. garrisoning of Germany was not originally meant to be permanent. The United States deployed troops to Germany early in the Cold War for two famous reasons: to keep the Soviet army out (that is, deterred from conquering West Germany and using it as a springboard to threaten the United States) and to keep West Germany down, which meant preventing its remilitarization and becoming a nuclear power. That would have alarmed European partners and potentially scared the USSR into starting World War III.
