No, they started the war in 39, when they agreed to carve up Poland with the Nazis. Hitler wasn’t going to attack without the Non-Aggression Pact.
It's hard to argue with that.
Funny thing is that the Soviets invading eastern Poland in 1939 (and the Baltic states in 1940) probably helped save them since it pushed the demarcation line quite a large distance to the west.
Without that extra buffer it's a pretty fair guess Moscow would probably have been taken in Oct of 1941.