Communist revolutions in Europe
In war-torn Imperial Russia, the liberal February Revolution toppled the monarchy. A period of instability followed, and the Bolsheviks seized power in the October Revolution. The ascendant communist party soon withdrew from the war with large territorial concessions by the Treaty of Brest-Litovsk. It then battled its political rivals in the Russian Civil War, including invading forces from the Allied Powers. In response to Lenin, the Bolshevik Party and the emerging Soviet Union, anti-communists from a broad assortment of ideological factions fought against them, particularly through the counter-revolutionary White movement and the peasant Green Army, the various nationalist movements in Ukraine after the Russian Revolution and other would-be new states like those in Soviet Transcaucasia and Soviet Central Asia, through the anarchist-inspired Third Russian Revolution and Tambov Rebellion.
By 1921, due to exhaustion, the collapse of transportation and markets, and threats of starvation, even dissident elements of the Red Army itself were in revolt against the communist state, as shown by the Kronstadt rebellion. However, the multiple anti-Bolshevik forces were uncoordinated and disorganized, and in every case operated on the periphery. The Red Army, operating at the center, defeated them one by one and regained control. The complete failure of Comintern-inspired revolutions was a sobering experience in Moscow, and the Bolsheviks moved from world revolution to the theme of socialism in one country, Russia. Lenin moved to open trade relations with Britain, Germany, and other major countries. Most dramatically, in 1921, Lenin introduced a sort of small-scale capitalism with his New Economic Policy (or NEP). In this process of revolution and counter-revolution the Union of Soviet Socialist Republics (USSR) was officially born in 1922.
The Leninist victories also inspired a surge by the world Communist movement: the larger German Revolution and its offspring, like the Bavarian Soviet Republic, as well as the neighboring Hungarian Revolution, and the Biennio Rosso in Italy in addition to various smaller uprisings, protests and strikes, all proved abortive.
The Bolsheviks sought to coordinate this new wave of revolution in the Soviet-led Communist International, while new communist parties separated from their former socialist organizations and the older, more moderate Second International. Despite ambitions for world revolution, the far-flung Comintern movement had more setbacks than successes through the next generation, and it was abolished in 1943. After the Second World War when the Red Army occupied most of Eastern Europe, Communists would come to power in the Baltic states, Poland, Hungary, Czechoslovakia, Romania, Bulgaria, and East Germany.