 As early as 1925 , Adolf Hitler vaguely declared in his political manifesto and autobiography Mein Kampf that he would invade the Soviet Union , asserting that the German people needed to secure Lebensraum ( " living space " ) to ensure the survival of Germany for generations to come . On 10 February 1939 , Hitler told his army commanders that the next war would be " purely a war of Weltanschauungen ... totally a people 's war , a racial war . " On 23 November , once World War II had already started , Hitler declared that " racial war has broken out and this war shall determine who shall govern Europe , and with it , the world . " Racial policy of Nazi Germany viewed the Soviet Union ( and all of Eastern Europe ) as populated by non @-@ Aryan Untermenschen ( " sub @-@ humans " ) , ruled by " Jewish Bolshevik conspirators " . Hitler claimed in Mein Kampf that Germany 's destiny was to " turn to the East " as it did " six hundred years ago " . Accordingly , it was stated Nazi policy to kill , deport , or enslave the majority of Russian and other Slavic populations and repopulate the land with Germanic peoples , under the Generalplan Ost . The Germans ' belief in their ethnic superiority is discernible in official German records and by pseudoscientific articles in German periodicals at the time , which covered topics such as " how to deal with alien populations " . 
