But as the war continued, it was Hitler’s political dogma that ensured the failure of his military aims. His worst military decisions – the refusal to let units withdraw to better positions, the obsession with towns that had strong psychological overtones (such as Leningrad and Stalingrad), and the political interference with the army – all these stemmed from his fears of political consequences. Politically motivated plans can be fatal to world conquest as to car factories.

— Blitzkrieg by Len Deighton (Page 64 - 65)