The Great Purges of 1937-1939 undoubtedly inflicted a massive blow to the Soviet Union's military capability. Up until that point, the Soviet Union embraced the rather nebulous ideas that embodied the German Blitzkrieg, (combined-arms cooperation, maneuver, mechanization, and concentrated attacks into the enemy's operational and strategic depth) and crystallized them into a formal military doctrine: deep battle. However many of the Red Army's best thinkers, including those who had formulated deep battle, were swept up in Stalin's Great Purges, and deep battle was thrown out of Soviet military strategy. This is but one of many effects that the purges had (including a loss of an experienced officer corps, a wave of early promotions, the disbandment of the mechanized corps etc.), but I feel it is one of the most important, since it changed, in a very fundamental way, how the Red Army fought. Therefore, my question is: what if the purges were never carried out? What if the Red Army retained it's sophisticated strategic, operational, and tactical doctrine and had it's old cadre of military thinkers commanding it? What if the Red Army fought with the same competence that marked their performance during the latter periods of the war, when they had fully relearned and applied the concepts of deep battle? What effects would this have on the war with Germany, and in the long term what are some of the possible effects that this could of had on a post-war world?