From the little I know, not being half as much an expert as you guys, as far as Hitler's biggest mistakes go, I would point to the invasion of Russia, and the subsequent war on two fronts as a given, and wrt the war on the Eastern front, a number of other factors. As has already said, Hitler being supreme commander of the army; whilst sometimes he displayed tactical insight, at other times his vision was clouded by his ideology. What was his ultimate purpose at Stalingrad? To cut off the Russian supply lines, capture the Caucasus oilfields, or to subdue the city that bore Stalin's name? Why was he so slow to ok the advance to Moscow, despite Guderian's inisistence on the need to advance before the autumn/winter set in? The battle of Kiev, although technically a victory for the Wermacht lost them 1 million men, and commited the army to a winter assault on Moscow, further forces being diverted to Leningrad.
Later on, the fiasco of Kursk/Zitadelle was also a disaster on many fronts. Not least the problems with the new German tanks, Porsche Ferdinands without the gunshields and with vulnerable fuel lines and lack of machine gun fire necessitating artillery cover etc. etc. and Panthers still not able to match up to the versatility of the T34s (Guderian himself said "
"...they (Panthers)
burnt too easily, the fuel and oil systems were insufficiently protected, and the crews were lost due to lack of training.") The sheer amount of different tank designs meant that spare parts were not forthcoming to repair them during the battle, whilst the Russians use of the T34, and little else, meant that they could be recycled during lulls in the battle, and tank numbers quickly built up again.
Another issue is the misuse of resources by Hitler and those around him, in particular Himmler in his appropriation of new armaments manufactured in 1944 for the Volksturm and SS regiments, meaning the Wehrmacht weren't adequately re-equipped, never mind starving, the bread ration in many cases having been reduced to 70g a day. Add to this the supply difficulties, the weather, indaequate winter uniforms. After the failure of Zitadelle, it was all over.
Someone has probably said all this before, I didn't have time to read the whole thread! Forgive me for not answering the question also, as I realise I have listed a whole load of mistakes which add up to a big one, rather than one big one in itself!
