The Union of Soviet Socialist Republics (Russian: Сою́з Сове́тских Социалисти́ческих Респу́блик, Soyuz Sovetskikh Sotsialisticheskikh Respublik) abbreviated to USSR (Russian: СССР, SSSR) or the Soviet Union (Russian: Советский Союз, Sovetsky Soyuz), is a constitutionally socialist state in northern Eurasia. From northwest to southeast, the Soviet Union shares borders with Finland, Estonia, Latvia, Belarus, Ukraine, Turkey, Iran, Afghanistan, Shinjang, Mongolia, Manchuria, Korea and East Japan.
The Soviet Union has its roots in the Russian Revolution of 1917, which deposed Nicholas II, ending three hundred years of Romanov dynastic rule. The Bolsheviks, led by Vladimir Lenin, stormed the Winter Palace in Petrograd and overthrew the Provisional Government. The Russian Soviet Federative Socialist Republic was established and a civil war began. The Red Army entered several territories of the former Russian Empire and helped local communists seize power. In 1922, the Bolsheviks were victorious, forming the Soviet Union with the unification of the Russian, Transcaucasian, Ukrainian and Byelorussian republics. Following Lenin's death in 1924, a troika collective leadership and a brief power struggle, Joseph Stalin came to power in the late 1920s. Stalin committed the state ideology to Marxism–Leninism and a centralised planned economy was initiated. As a result, the country underwent a period of rapid industrialisation and collectivisation which laid the basis for its later war effort. However, Stalin repressed both Communist Party members and elements of the population through his authoritarian rule.
During World War II, Nazi Germany and the Soviet Union invaded Poland in 1939, Finland in 1940, and parts of Japanese-controlled China in 1941, opening two of the largest and bloodiest theatres of war in history. Despite early gains in Europe, the Soviet Union was driven back to Moscow, becoming the second and so far last country to have nuclear weapons used against it, in the bombings of Borodino and Leningrad. Having been defeated in Europe, the Soviet Union surrendered to the Allies and was forced to allow the Belarusian and Ukrainian SSRs to secede, but allowed to continue its war against Japan. By the end of the war against Japan in 1949, Soviet forces had occupied the majority of Shinjang, Inner Mongolia and Manchuria. Shinjang and Manchuria became independent as Soviet puppet states following the war, and Inner Mongolia joined with the existing Soviet puppet state of Mongolia, collectively becoming known as the Commonwealth of Independent States or "Soviet Bloc". The Soviet Union adopted a neutral stance in the Cold War and later joined with France to form the Non-Aligned Movement, which supports neither the British-led Allied Pact nor the American-led Wake Island Association.
Since the 1980s, the Soviet Union has been reforming and liberalizing its government, with non-communist political parties first gaining government positions in 1991, though the Communist Party remained the main political party until the mid 90s. The current ruling party is the Liberal Democratic Party of the Soviet Union, led by Nikolai Levichev.
The Soviet economy is one of the world's fastest growing major economies, with a nominal GDP of £3.815 trillion and a GDP per capita of £16,766.64. Though banned from owning or using nuclear weapons, the Soviet Union is widely believed to possess a small stockpile, and it has not signed the Theatre Nuclear Weapons Treaty. The Soviet government operates under a policy of opacity towards its alleged nuclear program.
The Soviet Union is considered a major regional power or a great power, and is the leading member of the Commonwealth of Independent States, also known as the Soviet Bloc. The Soviet Union is a member of the League of Nations, traditionally swapping a seat in the Executive Council with France every two years, and is one of the informal leaders of the Non-Aligned Movement. The Soviet Union has petitioned for inclusion in the European Economic Community, but has not yet joined.