structural:expansion, structural:reformatting
Joseph Stalin

Stalin bore the greatest responsibility for some of the disasters at the beginning of the war (for example, the Battle of Kiev in 1941), but equally deserves praise for the subsequent success of the Soviet Red Army, which depended on the unprecedentedly rapid industrialisation of the Soviet Union, which Stalin's internal policy had made the first priority throughout the 1930s.Stalin's Great Purge of the Red Army in the late 1930s involved the legal prosecution of many of the senior command, many of whom the courts convicted and sentenced to death or to imprisonment.

The executed included Mikhail Tukhachevsky, a proponent of armoured blitzkrieg. Stalin promoted some obscurantists like Grigory Kulik who opposed the mechanisation of the army and the production of tanks, but on the other hand purged the older commanders who had held their positions since the Russian Civil War of 1917–1922, and who had experience, but were deemed "politically unreliable". This opened up their places to the promotion of many younger officers that Stalin and the NKVD regarded as in line with Stalinist politics. Many of these newly promoted commanders proved terribly inexperienced, but some later became very successful. Soviet tank-output remained the largest in the world.

From the foundation of the Red Army in 1918, political distrust of the military had led to a system of "dual command", with every commander paired with a political commissar, a member of the Communist Party of the Soviet Union. Larger units had military councils consisting of the commander, commissar and chief of staff – commissars ensured the loyalty of the commanding officers and implemented Party orders.

Following the Soviet occupation of eastern Poland, of the Baltic states and of Bessarabia and Northern Bukovina in 1939–1940, Stalin insisted on the occupation of every fold of the newly Sovietized territories; this move westward positioned troops far from their depots, in salients that left them vulnerable to encirclement. As tension heightened in spring, 1941, Stalin desperately tried not to give Hitler any provocation that Berlin could use as an excuse for a German attack; Stalin refused to allow the military to go on the alert – even as German troops gathered on the borders and German reconnaissance planes overflew installations. This refusal to take necessary action was instrumental in the destruction of major portions of the Red Air Force, lined up on its airfields, in the first days of the German–Soviet war.

At the crisis of the war, in the autumn of 1942, Stalin made many concessions to the army: the government restored unitary command by removing the Commissars from the chain of command. Order 25 of 15 January 1943 introduced shoulderboards for all ranks; this represented a significant symbolic step, since after the Russian Revolution of 1917 shoulderboards had connotations as a symbol of the old Tsarist régime. Beginning in autumn 1941, units that had proved themselves by superior performance in combat were given the traditional "Guards" title.

These concessions were combined with ruthless discipline: Order No. 227, issued on 28 July 1942, threatened commanders who retreated without orders with punishment by court-martial. Infractions by military and politruks were punished with transferral to penal battalions and to penal companies which carried out especially hazardous duties, such as serving as tramplers to clear Nazi minefields. The order stipulated to capture or shoot "cowards" and fleeing panicked troops at the rear where blocking detachments were ordered to be set up. In the first three months after Order No. 227 was promulgated 1,000 retreating troops were shot and 24,993 were sent to penal battalions. By October 1942 the idea of regular blocking detachments was quietly dropped, By 29 October 1944 the units were officially disbanded.

As it became clear that the Soviet Union would win the war, Stalin ensured that propaganda always mentioned his leadership of the war; he sidelined the victorious generals and never allowed them to develop into political rivals. After the war the Soviets once again purged the Red Army (though not as brutally as in the 1930s) and demoted many successful officers (including Zhukov, Rodion Malinovsky and Ivan Koniev) to unimportant positions.