The Red Army was "the main engine of Nazism’s destruction," writesBritish historian and journalist Max Hastings in "Inferno: The World at War, 1939-1945." The Soviet Union paid the harshest price: though the numbers are not exact, an estimated 26 million Soviet citizens died during World War II, including as many as 11 million soldiers. At the same time, the Germans suffered three-quarters of their wartime losses fighting the Red Army.

"It was the Western Allies’ extreme good fortune that the Russians, and not themselves, paid almost the entire ‘butcher’s bill’ for [defeating Nazi Germany], accepting 95 per cent of the military casualties of the three major powers of the Grand Alliance," writes Hastings.

Don't forget how the Soviet Union saved the world from Hitler (the Washington Post)

Yes, that happened despite Stalin's crimes and blunders.