The Communists won a civil war which lasted three years in Russia. Within the three years the Civil war was happening, the Communists faced a lot of opposition which wanted to remove the Communists from the Russian government. However all of the opposition weren’t able to succeed in removing the Communist government for many reasons such as Divisions within the opposition which saw that each group had their own agenda other than overthrowing the Communist government which resulted to the Russian civilians not supporting them & the Communists had the opportunity to crush them, winning the Civil War.
Another reason the Communists won the Civil War was Invention of the Foreign States. All of the allies wanted Russia to stay in the war however the Communist rule was being financed by Germany which the allies feared they won’t continue the fight against Germany. However the Treaty of Brest-Litosvsk in March 1918 made the allies attitudes harden and as soon as the end of the First World War, all of the allies turned against to do a major offensive against the Bolsheviks as they were alarmed by the creation of Comintern and the spread of Revolution in Germany & Central Europe. During the Civil War, the allies relied on supplies aboard which arrived in the right places at the time which made it easier for the Communists to defeat them.
Another reason was the Organisation of the Reds. The Communists dominated Russia as they had control of Petrograd, Moscow which was the most important industrial areas which had most of Russia’s railway network. These territories were unbroken by areas under opposition control. They gave the Communists easy access munitions & send troops to areas to where it’s needed and they were able to communicate effectively. Therefore the Communists were able to win the Civil war because the Red Army was able to defeat the opposition one by one.