Hitler when he entered Russia.
Stalin was dictator in Russia .
USSR truly entered the war with the invasion of Russia. They were wasting the time with the Russo-Finnish war.
Yes, soviet troops entered Berlin in May 1945
Joseph Stalin was the leader of Russia in World War 2.
The US entered WWII when the Japanese bombed pearl harbor in Hawaii.
Because Russia invaded Finland, and then Germany invaded Russia (Soviet Union) so the Finnish wanted revenge so entered the war on Germany's side
During the world war 2
America entered the war
In world war 2 Russia and America were allies, against Germany