On March 9, 1918, the ascendant Bolshevik Party formally changes its name to the All-Russian Communist Party. It was neither the first nor the last time the party would alter its name to reflect a slight change in allegiance or direction; however, it was the birth of the Communist Party as it is remembered to history. With this change, the cadre that had brought down both Czar Nicolas II and the Provisional Government that followed his abdication announced itself to the world as a communist government, and it would unilaterally rule the emerging Union of Soviet Socialists Republics until 1991.
The Bolsheviks—Russian for "members of the majority"—had been the more aggressive faction of the Russian Social Democratic Labour Party, pushing for a more militant membership and explicitly endorsing the nationalization of land. After the February Revolution of 1917, as workers across the country organized themselves into political units known as soviets, the Bolsheviks' support was more fervent and more widespread than that of the Provisional Government, which they eyed with distrust.
As revolution continued to spread throughout Russia following the October Revolution, the Bolsheviks acted quickly. They withdrew Russia from World War I, the stresses of which are often cited as a major cause of the revolution. They also began seizing and redistributing imperial lands. By early 1918, factories had been turned over the soviets, private property had officially been abolished, and Russia had become the Russian Soviet Socialist Republic, soon to be the largest constituent republic of the USSR. It was a stunning victory for Lenin, the forces of Russian socialism, and Marxists around the world. In keeping with the Marxist axiom that communism would inevitably replace capitalism by means of socialism, the Bolshevik Party rebranded as the Communist Party.
READ MORE: How Are Socialism and Communism Different?
For the rest of the Soviet Union's existence, the leadership of the party and the leadership of the nation were one and the same. Under this leadership, the USSR became one of the two great economic and military powers of the world, sacrificing more of its people than all other Allied nations combined in World War II and emerging as the only serious competitor to the American juggernaut. Communist rule was notorious for authoritarian rule, the imprisonment of political dissidents, and the stifling of dissent, particularly under Lenin’s successor, Joseph Stalin.