The Allied powers launch an unsuccessful military intervention in support of anti-communist forces.

In the meantime, both the Bolsheviks and White movement carry out campaigns of deportations and executions against each other, known respectively as the Red Terror and White Terror.

By the end of the violent civil war, Russia's economy and infrastructure are heavily damaged, and as many as ten million perish during the war, mostly civilians.

Millions become White émigrés, and the Russian famine of 1921–1922 claims up to five million victims. 

Lenin and his aides form the Soviet Union, by joining the Russian SFSR into a single state with the Byelorussian, Transcaucasian, and Ukrainian republics, on December 30, 1922.

Eventually internal border changes and annexations during the second World War will create a union of fifteen republics; the largest in size and population being the Russian SFSR, which will dominate the union for its entire history politically, culturally, and economically.