Hitler himself did, with help from a lot of others internally and externally.
There were reasons why he was jokingly called "Gröfaz" (GRÖssest Feldzherr Alle Zeiten - the greatest commander of all times). His merits as a military strategist, operational or tactical commander were at best mediocre. It's a bit like a person who has read a smidgen of law or medicine, behaving like a full-fledged lawyer or doctor - it always ends in pain.
I'm aware of that it may seem that H. were a great strategist in the way he jockeyed Germany into position before the outbreak of the war. But I would tend to disagree as most of his actions were of an ideological rather than strategic nature. One could even argue that it got the allies even closer together and therefore was really BAD strategy.
The nazifying of the military and civilian top echelon's was another example of a bad call. There is only one example in history, where that kind of ploy has been beneficial to military strength - Napoleon. In N's case it was because he got rid of incompetents who got their position from family ties and prestige alone, giving room for those ambitious an competent lower officers who had previously been barred from higher rank.
Blindly believing in competition, many functions were set up with redundancy, making the ppl charged with the executing of the same functions fight each other as much as the problem at hand - and giving them an easy out by blaming someone else if it hit the fan. There were a lot of empires being built within the ranks.
He also showed four dangerous vices - playing too close to his chest, making impossible demands, being unrealistic and being indecisive.
1.) Hitler seemed to distrust everyone but himself and a small cadre of yessirs close to him. He thereby failed to delegate authority to those with the best ability to make well-formed decisions. He also kept the plans for the war mighty close to himself, sometimes stupidly.
Two short examples, the first being Rommel in Africa: He didn't get the troops he asked for, but never knew it was because of the coming operation Barbarossa. So he was kept in the dark about such a crucial development, believing his operation was high-priority.
Second being the bomber role of the me262: This was crucial to H's anti-invasion plans - even so he never told those in charge of getting the planes ready the reason for carrying bombs. The result being that request was ignored, H. having a fit of anger, H. and Luftwaffe coming even further apart.
2.) H. made the same mistake as the generals of ww1 -- making plans at the table, getting out of touch with hard reality. Like his firing of generals on the eastern front, just because they took reality into account. Or telling Paulus not to surrender, but to fight to the last man -- like some romantic battlefield tale for adolescents.
3.) Well, let's just say Barbarossa… Or the defense of Berlin.
4.) H. loved to think of himself as a military mastermind, coming up with this and then that grandiose plan for success, but often failed to grasp the point of decision. Like when H. wanted to launch a surprise offensive against USSR. But then demanded a halt of the main concentration of the German armies to assist secondary forces in seizing subsidiary objectives. (The OKH produced an elegantly simple and direct plan for the campaign but failed to counter Hitler's objections.)
H. failed to grasp international political and diplomatic strategy. An example:
As Fleming wrote, he could easily have ended the war in the west after Dunkirk, by unilaterally declaring cease-fire and then setting up "neutral" benevolent "puppet"-governments in all of Western Europe. Thereby he would be ridding himself of the need for occupation while still being able to skim the cream of the top, setting up defense treaties etc. He would then more or less force GB either to sue for peace or fight a war with a Germany they no longer had physical contact with. As Fleming stated, it would take more than even the rhetoric of Churchill to keep GB in the war without a clear and present threat, and with the exile-governments wanting to go home. According to him, the one thing that strengthened the resolve of the British were adversity and danger.
Without an active war in Western Europe, and with Germany as a "benevolent" victor, the US would probably not have entered into it. GB and US would after all have had to trespass or occupy "neutral" territory to even get to Germany -- political suicide.
With no credible threat from the west, H. would only have to keep Mussolini's adventures in check to be able to concentrate all his efforts on USSR. A USSR that both GB and US feared implicitly. Judge for yourself what might have happened.
Lastly, barring Hitler as the cause for the fall of Germany I'd say it's a hard call to make. I suppose USSR is high on the list since the majority of casualties where in the east. But without the bombing of German factories and without the diversion of troops to the west USSR might well be named in german today…
/Scat
