The Era of Stagnation (Russian: Период застоя, Stagnation Period, also called the Brezhnevian Stagnation) was a period of negative economic, political, and social effects in the Soviet Union, dubbed by a generic term "stagnation", which began during the rule of Leonid Brezhnev (1964–1982) and continued under Yuri Andropov (1982–1984) and Konstantin Chernenko (1984–1985). The stagnation was the result of failed central planning. When efforts to accelerate development through massive injections into heavy industry (Uskoreniye) failed, the Communist Party under Mikhail Gorbachev restructured (perestroika) the Soviet economy and government by introducing quasi-capitalist (Khozraschyot) and democratic (demokratizatsiya) reforms, which re-energized the Soviet Union but also inadvertently led to its dissolution in 1991 as a result of popular revolutions.
On the other hand, Brezhnev introduced a neologism "developed socialism" and declared its period (Russian: период развитого социализма) to start in 1971. The term stems from Khrushchev's promise of reaching communism in 20 years.
The 1964–82 period in the Soviet Union began hopefully but devolved into disillusionment. Historians, scholars, and specialists are uncertain what caused the stagnation, with some arguing that the planned economy suffered from systemic flaws which inhibited growth. Others have argued that the lack of reform, or the high expenditures on defense, led to stagnation. The majority of scholars set the starting year for economic stagnation at 1975, although some claim that it began as early as the 1960s.