After Stalin's death in 1953, Nikita Khrushchev became leader of the Soviet Union and aimed to reduce Stalin's harsh policies through "destalinization". However, he failed to reform communist rule in Eastern Europe, leading to uprisings. In 1964, Leonid Brezhnev replaced Khrushchev and cracked down on dissent while asserting Soviet control over satellite states. He invaded Czechoslovakia in 1968 to prevent liberalization. Under Brezhnev's rule, tensions grew between the Soviet Union and China but remained peaceful. In the 1970s, detente policies under Nixon and Brezhnev lessened tensions between the US and USSR through arms control talks, but Reagan ended detente in the 1980s.