The Bolsheviks did not overthrow any leaders of the soviet Union. The Bolsheviks were the people who created the Soviet Union lead by Vladamir Lenin.
The Soviet Union was created by the Bolsheviks, run by a peoples communist party.
Bolsheviks
After seizing power, the Bolsheviks became the Communist Party of the Soviet Union.
Communism
The Bolsheviks were communist and went on to form the Communist Party of the Soviet Union. The Mensheviks were socialists with different ideals who split from the Bolsheviks.
The leader of the Soviet Union during WW2 was Joseph Stalin.
Vladimir Lenin and the Bolsheviks did in 1917.
The Bolsheviks led by Vladimir Lenin led the Russian Revolution in 1917 which in 1922 the name officially became the USSR Union of Soviet Socialist Republics or Soviet Union.
The Bolsheviks ruined The Soviet Union's economy and not to mention the civil war that raged between them and their opponents who formed the White Army
The Bolsheviks came to power during the Russian Revolution of 1917's October Revolution phase and founded the Soviet Union.
Gorbachev
The Soviet Union