Ever since the Diktat of Versailles, the great majority of the German population believed that they had been robbed of victory in the First World War and they therefore wanted rearmament followed by a war of revenge. As Marshal Foch said when the terms were published in 1919 “This is not a peace treaty - it is a twenty year truce.” All German political parties (including the Communists) wanted the return of the lost eastern provinces and Germany had therefore already started to re-arm (in defiance of the Versailles Treaty) in the 1920s, long before the Nazis came to power in 1933. As Foch predicted, it took Germany twenty years to recover from its defeat whereupon it started the desired war of revenge in 1939. The fact that the Nazis had meanwhile come to power was irrelevant. Hitler’s immediate predecessor as Chancellor (General Schleicher) had already announced preparations.
The same predictability applied to the Holocaust. Regrettable, pre-existing virulent anti-Semitism was exacerbated by Germany’s defeat. The Jewish minority provided the ideal scapegoat. It was already hated for the fact that its members (only half a million out of a total population of 80 million) were disproportionately successful, completely dominating business and the professions. This caused intense jealousy. Thus, as early as 1907 the Kaiser (Wilhelm II) informed the British Ambassador (Sir Edward Grey) that the Jews “need stamping out.” Like other Germans, Wilhelm’s anti-Semitism reached fever pitch after the defeat of 1918. The following year he wrote to General von Mackensen “let no German rest until these parasites (the Jews) have been destroyed and exterminated. I believe the best way would be gas.” [see: John Rohl, The Kaiser & his Court: Wilhelm II and the Government of Germany, Cambridge University Press, (1996)].
Thus, after catastrophic defeat in the First World War and the ensuing punitive peace treaty, German public opinion was revanchist and blamed the Jewish “stab in the back” for robbing it of expected victory. What was therefore wanted was a war of revenge, which it was assumed would result in victory if Jewish treason could be prevented by genocide. Hitler achieved power by more effectively advocating the desired policy than his opponents (eg General Schleicher, whom he managed to replace as Chancellor in 1933). Human nature being what it is, a defeated people will blame an unpopular minority. Thus, after its defeat in the Franco-Prussian War of 1870, French public opinion supported the anti-Dreyfusard movement which alleged Jewish treason.