Soviet Union

The Soviet Union, officially the Union of Soviet Socialist Republics, was a one-party socialist state that spanned much of Eurasia and became one of the two superpowers of the twentieth century.

It was formally established on 30 December 1922 through the Treaty of Union, which bound together the Russian, Ukrainian, Belarusian, and Transcaucasian Soviet republics under the leadership of the Bolshevik (Communist) Party in the aftermath of the Russian Revolution of 1917 and the ensuing civil war. The state was founded on Marxist-Leninist ideology, abolishing private ownership of major industry and agriculture in favour of centralised state planning. Under Joseph Stalin, who consolidated power after Lenin's death in 1924, the USSR underwent rapid, forced industrialisation and the collectivisation of agriculture, transforming a largely agrarian society into an industrial power at enormous human cost, including widespread famine, mass deportations, and the political purges and labour camps of the Gulag system. The Soviet Union played the decisive role on the Eastern Front in defeating Nazi Germany in the Second World War, suffering by far the largest losses of any combatant, with tens of millions of deaths. Victory left it dominant across Eastern Europe, where it installed allied communist governments, and inaugurated the Cold War rivalry with the United States, an ideological, military, and technological contest that shaped global politics for four decades and included a vast nuclear arms race and the early space race, in which the USSR launched the first satellite and the first human into orbit. The Soviet system delivered universal education, healthcare, and industrial growth, but suffered from chronic economic inefficiency, shortages, censorship, and political repression. From the mid-1980s the reforms of Mikhail Gorbachev, known as perestroika (restructuring) and glasnost (openness), sought to revitalise the system but instead unleashed forces that the central government could not contain. Nationalist movements grew in the constituent republics, the communist monopoly on power eroded, and the Eastern European satellite states broke away in 1989. After a failed hardline coup in August 1991, the union rapidly disintegrated; the Belavezha Accords of December declared it dissolved, and Gorbachev resigned on 25 December 1991. The USSR formally ceased to exist on 26 December 1991, fragmenting into fifteen independent successor states.

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