On December 26, 1991, at the last meeting of the Supreme House of Soviet Republics of the USSR, the Soviet Union announced its dissolution, and the Union of Socialist Republics, founded on December 30, 1922, collapsed as it was about to celebrate its 69th birthday. After World War II, with the help of the Soviet Union, regimes in Eastern Europe were established. Therefore, these countries have great laziness and limitations on the operation mode of the Soviet Union. Then in 1947, with the advent of the "Truman Doctrine," the Cold War began in the United States and the Soviet Union.
In order to oppose the United States, Stalin began to increase his control over the countries of Eastern Europe militarily, politically, and economically, hoping for the integration of Korea and Japan. Because the countries of Eastern Europe were forced to copy the Stalin model and forcibly interrupted their own road of building socialism according to their national conditions, all systems were extremely inconsistent. This led to an extremely slow economic development, which culminated in a severe economic downturn in the 1980s, and the political situation was followed by fierce turmoil. In order to cope with the domestic situation, the ruling parties of various countries have been forced to abandon centralized politics, take "democratic socialism" as the goal of struggle, and practice political pluralism. This greatly increased the power of the villain and began to build a new regime through democratic votes. Then, from 1989 to 1990, the Communist and Workers' Parties of Poland, Hungary, Germany, Romania, Bulgaria, Czechoslovakia, Yugoslavia and other countries lost power. The social system has changed radically again. On 11 March 1990, Lithuania declared its independence, and since then other republics have made declarations of restoration or restoration of sovereignty. By December 16, 1991, kazakhstan, the last country of the Soviet republic, declared its independence, the Soviet Union had ceased to exist in name only. At the same time, after the August 19 Incident, the Communist Party of the Soviet Union also lost its position as the ruling party, and Gorbachev resigned as general secretary of the CPSU Central Committee.
Then, on December 26, 1991, the Supreme Council of Soviet Republics of the USSR held its last meeting, with only one content, and the Soviet Union officially disintegrated. The reasons for the collapse of the Soviet Union were expressed by many domestic and foreign scholars, roughly these points. During the Stalin period, a highly centralized approach to administration was adopted, which led to a long period of high concentration of power in the SOVIET Union. As a result, some officials are enriched and the phenomenon of corruption is extremely serious. The abuse of power for personal gain has become a common phenomenon. During this period, a number of privileged strata began to appear, and these people became a huge obstacle to the reform and development of the Soviet Union. Bureaucracy and persistent corruption have directly led to enormous social contradictions, and there have been several large-scale social unrest in the more than four decades that the Communist Parties in Eastern Europe have been in power.
Diplomatically, Gorbachev's constant concessions. He announced that the Soviet Union would abandon the dogma of Leonid Ilyich Brezhnev, renounce interference in the internal affairs of Eastern European countries, and allow the democratization of Eastern European countries. This led directly to a series of revolutions in Eastern European countries, causing the Soviet Union to completely lose control of Eastern Europe. In short, Gorbachev's series of concessions not only failed to ease the situation in the Soviet Union, but on the contrary, the turmoil in Eastern Europe continued to increase.
In terms of economy, after Gorbachev came to power, he tried to reduce social unrest by alleviating economic difficulties, so the Soviet economist Grigory Yavlinsky formulated the so-called 500-day plan for Gorbachev, but due to the lack of macro decisions and corresponding supporting measures, coupled with the practice of giving priority to the development of heavy industry, not only failed to get out of the economic predicament, but led to a continuous decline in the economy, the people's living standards continued to decline, resulting in strong dissatisfaction among the privileged classes and ordinary people. At the same time, the failure of monetary reform depleted the financial reserves of the Soviet government, causing public resentment to boil over and increasing the dissatisfaction of the Soviet people with the government. At the end of the collapse of the Soviet Union, not a single Soviet citizen stood up to defend the Soviet Union and the Soviet system. Yeltsin and other opponents, on the other hand, have won the support of the people.
So the immediate cause of the collapse of the Soviet Union was a series of reforms promoted by Gorbachev.