It was almost inevitable that the October Revolution would lead to a devastating Russian Civil War waged by forces hostile to socialism. Indeed, Lenin had predicted this very outcome. At the end of October 1917, a military advance by troops loyal to Kerensky reached the outskirts of Petrograd but was defeated by Red Guards organised by the Military Revolutionary Committee (MRC).
Just after October 1917, with Bolshevik power apparently secured in Petrograd and other cities, a coalition of monarchists, anti-Bolsheviks, liberals and regional forces came together to form the White Army. The Whites established a ‘government in-exile’ in the East under the command of Kolchak. In the Northern Caucasus, the Whites were supported by some Cossack troops and attacked newly-established Bolshevik strongholds. The Bolsheviks defended the revolution using the newly formed Red Army.
The Whites, with the help of the Czech Legion (a unit of the Russian Imperial Army during WW1), began gaining important territory and mobilising other forces. The Red Army grew to over a million men owing to the introduction of conscription in June 1918. (By 1920 it had grown to over four million). But by late 1918, the situation for this new army was looking bleak, as their strongholds were being surrounded by the Whites aided by foreign powers. Indeed, the survival of the revolution appeared inconceivable at this stage.
However, despite the initial successes of the Whites, by March 1919, the Red Army could record some victories. They had defeated Kolchak’s forces in the East, although General Denikin, having captured much of the south and Ukraine pushed northwards in conjunction with General Yudenich (assisted by Estonian troops). These armies reached the outskirts of Petrograd from different directions by October 1919. The Red Army managed to repel both these attacks. This would prove to be the closest the Whites would come to tipping the war in their favour.
In Ukraine, Denikin deliberately carried out anti-Semitic pogroms, linking Jews to the ‘evil’ of communism and presuming that targeting them could be used to appeal to the local population.
By the end of 1919, most of the Whites in the east surrendered. Kolchak was handed over to the Reds and executed. Wrangel replaced Denikin as leader of the White Army, but their numbers were now dwindling. In late 1920, remnants of the White Army fled, leaving the Bolsheviks to conquer the remaining regions. Pockets of resistance to Bolshevik control remained but the bloodiest parts of the Civil War were over by 1922.