Russian civil war

Bitter conflict in Russia (1918–21), which followed Russian setbacks in World War I and the upheavals of the 1917 Russian Revolution. In December 1917 counter‐revolutionary armies, the Whites, began to organize resistance to the October Revolution of 1917. The Red Army (Bolsheviks), improvised by Leon Trotsky, opposed them, resulting in civil war. The Bolsheviks eventually emerged victorious.

The war was fought in the regions of the Caucasus and southern Russia, the Ukraine, the Baltic, northern Russia, and Siberia.

Foreign involvement
The Bolsheviks also had to fight against the armies of Latvia, Lithuania, Estonia, and Finland. In northern Russia the British and French landed troops at Murmansk in June 1918, seized Arkhangelsk, and set up a puppet government. They continued outbursts of fighting against the Bolsheviks until October 1919. In Siberia, Admiral Kolchak, with the assistance of a Czech legion (composed of prisoners of war) and of Japanese forces that had landed at Vladivostok, established a White government in Omsk, western Siberia. Kolchak was captured and executed by the Bolsheviks in February 1920.

Bolshevik victory
While each of the White armies was engaged in an isolated operation, the Soviet forces were waging a single war. Trotsky was an active agent for the Bolsheviks in all the crucial operations of the war. The Bolsheviks put down peasant uprisings in 1920 and the Kronstadt uprising, a mutiny by sailors of the Russian Baltic Fleet at Kronstadt, outside Petrograd (St Petersburg), in March 1921. Bolshevik leaders Lenin and Trotsky used severe measures to achieve the suppression of the peasant uprisings. Whole villages were burnt to the ground and their populations executed, while the inhabitants of local villages were forced to watch as a warning not to oppose the Bolsheviks. The Bolsheviks were far superior to the Whites in both organization and propaganda. The last foreign forces left Soviet soil in 1922 when the Japanese evacuated Vladivostok. The Soviet government was recognized by Britain in 1924 and by the USA in 1933.

Long‐term impact on the USSR
The need to supply the Red Army led the Bolsheviks to introduce the policy of war communism. Although this was abandoned in 1921 in favour of Lenin's New Economic Policy, the effects of war communism were long‐lasting. The centralization of control over the economy and public life under the Bolsheviks accelerated during the civil war, and the Bolshevik government was more secure by 1922 than it had been in 1918. Tensions between the Bolsheviks and Russia's millions of peasants were heightened by the barbarity of the Red Army and the death of seven million Russians in the 1920–21 famine, that was caused by the requisitioning measures of war communism. The Bolsheviks remained suspicious of the peasants after the civil war, so they had little sympathy when many peasants opposed their collectivization programme of the early 1930s, or when over five million died in a famine that was a direct result of collectivization in Ukraine.

The civil war made a hero of Red Army leader Leon Trotsky, and this caused problems for Joseph Stalin in his campaign to lead the USSR after Lenin's death in 1924. Stalin had done little in the civil war, while Trotsky's status as a hero of the early revolution brought him many supporters. There followed an ideological struggle on the future of socialism, in which Stalin favoured establishing socialism in one country, while Lenin felt that world revolution was necessary. Gradually Stalin emerged as the dominant figure and Trotsky was expelled from the Soviet Communist Party in 1927, and exiled from the USSR in 1929. After defeating Trotsky, Stalin set about rewriting the history of the civil war. Trotsky's role was downgraded and his heroic status was systematically destroyed by Stalin's propaganda. The legacy of the civil war stayed with the Bolshevik's for many years.

The support given by the UK and France to the Whites in the Russian civil war remained a source of tension after 1924, when Britain evacuated the last Whites from the USSR. Relations between the former World War I allies were strained for many years, partly because of this support. The Bolsheviks believed that it showed that the capitalist nations wanted to destroy their communist revolution. Strained relations were still evident in 1939 when the USSR signed the Ribbentrop–Molotov pact, or Nazi–Soviet pact, with Germany. Although other issues, such as ideological differences, were important in explaining the long running rift between the USSR on one side and the UK and France on the other, their action in the civil war was a significant cause of the split.