Megalomaniac Hitler was not mean and nasty and but was quite cordial, personable and the life of the party most of the time. I guess he fooled Chamberlain. A pleasant personal demeanor and tough negotiator can go together.
Hitler was a charming mania? I would assume we want to avoid having another one of those in the coming election, ala Oh bah ma. Although O is giving the farm away, not assuaging the fears of enemies but of his countrymen.