 German military planners also researched Napoleon 's failed invasion of Russia . In their calculations , they concluded that there was little danger of a large @-@ scale retreat of the Red Army into the Russian interior , as it could not afford to give up the Baltic states , Ukraine , or the Moscow and Leningrad regions , all of which were vital to the Red Army for supply reasons and would thus have to be defended . Hitler and his generals disagreed on where Germany should focus its energy . Hitler , in many discussions with his generals , repeated his order of " Leningrad first , the Donbass second , Moscow third " ; but he consistently emphasized the destruction of the Red Army over the achievement of specific terrain objectives . Hitler believed Moscow to be of " no great importance " in the defeat of the Soviet Union and instead believed victory would come with the destruction of the Red Army west of the capital , especially west of the Western Dvina and Dnieper rivers , and this pervaded the plan for Barbarossa . This belief later led to disputes between Hitler and several German senior officers , including Heinz Guderian , Gerhard Engel , Fedor von Bock and Franz Halder , who believed the decisive victory could only be delivered at Moscow . Hitler had grown overconfident in his own military judgment as a result of the rapid successes in Western Europe . 
