I too have studied the Weimar Republic and have noted the parallels with America. A proud and prosperous nation (and incidentally, a very progressive one) is brought down by
humiliating military defeat and demoralizing economic stagnation. They also feel threatened by the air of social freedom and experimentation rocking their society. Germany had Versailles and the Great Depression, but they also had the Bauhaus, the German Impressionists and the Berlin School of Physics. It was a time of intellectual ferment and strange new ideas: homosexuality, sexual freedom, free thinking, the arts, experimentation and social freedom, Jazz and Flappers.

Its lower classes are given a taste of a better future, then cast down into despair. Its middle classes experience a renaissance of prosperity and progress, then suddenly find themselves in a period of decline and economic backsliding. Meanwhile, a rapacious upper class finds a way to profit from this state of affairs and single-mindedly exploits it in the most unscrupulous and unsustainable way.

Faced with a loss of confidence and a feeling of impending doom and helplessness, plus a cultural tradition of searching for the easy answer and the quick fix, a substantial portion of the people come to the conclusion that it can't be their fault, or the fault of those they emulate and wish to become, or even of historical forces over which no one has any complete control; but that it must be some kind of conspiracy of villains. They search for scapegoats.

Of course, there really ARE villains, and they find that serving up scapegoats and demagoguery are an easy shortcut to power.

Why these things happen is a matter of debate, and no doubt many historical social forces can be proposed to explain this state of affairs. And of course there are differences in country to country, and era to era. But the response to it, particularly the response of the middle class, is most clearly demonstrated in the example of Germany between the wars. A lot of nations may go through periods like this, and usually their national traditions and the innate common sense of their peoples pull them back from the abyss. But in others...

And of course their are variants of this phenomenon, such as in 20th century Italy, Spain, the USSR, Japan, Argentina and several MittelEuropan and South American fascist regimes. It doesn't always follow the exact same pattern. But in general, Fascism is the dictatorship of the middle class.

Oh, yes. There is one more disturbing historical parallel. Both twenty first century America and twentieth century Germany had a ready-made historical nucleus about which the forces of hate and vengeance could precipitate: racism. In both nations, the conditions of the main minority population had reached a point of relative success, both the Jews and the Negro. The contrast of their improving conditions (and the annoying political agitation which they engaged in to secure them) was simply an irritant a population in general decline could not tolerate. We also have Mexicans and Muslims.

When a people feel themselves the inheritors of an unstoppable historical process of progress and prosperity and suddenly feel it snatched away from them, they quickly and violently react. Fascism is the dictatorship of the middle class.