By 1917 the tsarist regime had basically collapsed under the strain of WWI. Russian industry lacked the capability to arm, equip, and supply its military forces and famine threatened the larger cities. Tsar Nicholas II, ignored warnings of social and political unrest, and in February 1917 workers filled the streets of Pertograd (St. Petersburg), demanding an end to the war and the removal of the tsar. Nicholas II abdicated on March 2 and a provisional government took power.

The revolution surprised the working-class parties even though they had called for it. Only in April, after the return of their exiled leader, Vladimir Ilich Lenin, did the Bolshevik Party assert itself. Lenin opposed the civil war and proposed that the party establish a proletarian dictatorship.

On October 24, under the direction of Lenin and Leon Trotsky, the Military Revolutionary Committee stormed the Winter Palace, completing the revolution and bringing the Bolsheviks to power.