And yet, we are oppressed by one nightmarish idea: if a dictatorship in Hitler's style should ever rise in America, all hope would be lost for ages. We in Germany could be freed from the outside. Once a dictatorship has been established, no liberation from within is possible. Should the Anglo-Saxon world be dictatorially conquered from within, as we were, there would no longer be an outside, nor a liberation. The freedom fought for and won by Western man over hundreds, thousands of years would be a thing of the past. The primitivity of despotism would reign again, but with all means of technology. True, man cannot be forever enslaved; but this comfort would then be a very distant one, on a plane with Plato's dictum that in the course of infinite time everything that is possible will here or there occur or recur as a reality. We see the feelings of moral superiority and we are frightened: he who feels absolutely safe from danger is on the way to fall victim to it. If only they would understand this experience! We are no inferior race. Everywhere people have similar qualities. Everywhere there are violent, criminal, vitally capable minorities apt to seize the reins if occasion offers, and to proceed with brutality.
-- Karl Jaspers The Question of German Guilt, p. 93
Question of German Guilt is one of those books that everyone really, really ought to read. It's quite short, and it deals in a perhaps less inflammatory way than Arendt with the existential moral questions raised by events in Europe during WWII. And I know, it's passe to compare things on the internet to Hitler and Nazis, but it really is something that should be on our minds more often.
By the way, if you want a good example of a what this might look like, read Raphael Carter's The Fortunate Fall, which, among other things, includes a fascinating depiction of the aftermath of a full-blown American, totalitarian empire.