Why did the author believe that having a leader like Hitler made it impossible to win the war in the nonfiction book, Lost Victories?

Manstein notes that with a leader like Hitler, it was impossible to win the war. Hitler started too many wars on too many fronts and his biggest mistake was the war against the Soviet Union. Manstein felt that after the fall of France it would have been possible to successfully invade Great Britain, though he was not in a position to get Hitler to adopt this strategy. Manstein made the point that from the German General Staff down to non-commissioned officers, the strength of the German army was the ability of commanding officers to make their own decisions on tactics and immediate objectives. This idea of the personal initiative of the German soldier is quite different from the commonplace stereotype of the obedient German under Hitler.

Manstein showed this trait of innovation with his plan to introduce a large German tank force through the Ardennes region of Southern Belgium into Northern France. This was an unexpected stroke in that the Ardennes region is largely heavily wooded and low mountains and was seen as a difficult to put through a large number of troops. Yet, Manstein put this plan forward with the backing of his Army Group A commander Von Rundstedt. Manstein got Hitler to adopt the plan that resulted in a totally successful attack that destroyed the French Army in May and June 1940. Manstein would have liked to use the plan for Operation Sealion, an amphibious invasion of Great Britain shortly after, but Hitler never really backed this plan. Instead, Hitler ordered the attack on the Soviet Union a year later, in June 1941.