(1918–20) Conflict between the newly formed Bolshevik government and its Red Army against the anti-Bolshevik forces in Russia.
The unfavourable Treaty of Vladimir Lenin to break with the Bolsheviks and join the right-wing Whites and their volunteer army under Anton Denikin . In an attempt to create another front in World War I , the Allies gave limited support to the Whites. The Moscow government responded to the growing anti-Bolshevik movement by expelling Menshevik and Social Revolutionary deputies from the government, and it began a campaign of "Red terror" that gave increased powers to the secret police (Cheka) to arrest and execute suspects. The Bolsheviks maintained control over the heart of the country, but the anti-Bolsheviks gained power in Ukraine and Omsk, where {{link=Kolchak, Aleksandr Vasilyevich">Aleksandr Kolchak and other dissident groups joined together to fight the Red Army. Confused by the struggles between communists, Russian Whites, and Ukrainian nationalists, the Allies withdrew their support by 1919. After early military successes against the Red Army, the White forces under Kolchak were defeated by early 1920. Other White troops under Nikolay Yudenich failed to take St. Petersburg. The last White stronghold in the Crimea under Pyotr Wrangel , Denikin's successor, was defeated in November 1920, ending the Russian Civil War.