Nazi Germany invaded the Soviet Union on 22 June 1941. Stalin was taken by surprise.
Stalin's government were unprepared for war because many senior officers were purged in the 1930s.
1,200 Soviet aircrafts were destroyed in the first 24 hours of the war.
A million Russian troops were killed after 3 weeks of war. 20 million people were living under German rule.
The danger posed to Stalin's regime was that it might collapse in defeat. The fear was that it would mirror the fall of Tsarism.
The Soviet Union was ruthless once it was roused to war because it was a highly centralised regime.
An advantage of Stalin's regime in wartime was that it was a highly effective government. The State Defence Committee conducted the war.
Stalin was in charge of military command. He left generals alone to sort out military campaigns.
Stalin addressed "brothers and sisters" in his first wartime speech. Stalin appealed to the "motherland".
Stalin appeal to Russian nationalism over loyalty. The war became known as the "Great Patriotic War" in Russia.
Hitler hoped that non-Russian national minorities would rise up against Stalin's regime. Ukrainians and Baltics were 2 examples.
Thousands of national minorities collaborated with German forces after suffering. Stalin responded to this by transferring a million minority people out of fear of disloyalty.
Ukrainians, Germans and Chechens were national minorities that Stalin transferred East.
The Stalinist procedure of purges continued in wartime. Terror was also exploited in wartime.
Stalin ordered that deserters and "cowards" were to be shot after Stalingrad was on the verge of defeat in 1942. 13,000 people died as a result of these "crimes".
Prisoners of war came under suspicion for "crimes" in 1945. They were feared to be disloyal because they had become tainted by Western values in captivity.
Many prisoners of war were transferred to Soviet labour camps.
Stalin addressed the grievances of army officers by reducing the role of political commissars attached to army units. He restored the special badges of rank.
Vast numbers of the armed forces were encouraged the join the Communist Party. Half the members were from the army or navy by the end of the war.
Nationalism was emphasised in wartime propaganda. Stalin claimed Russia's victory in war was a victory for communism over fascism.
The idea of a "People's war" was played down. The "Great Patriotic War" was hailed as a victory.
D. Volkogonov stated that Stalin "ruled like an absolute monarch" during wartime.