To be fair, everyone dismissed Hitler as an incompetent no-hoper both before and after his failed coup attempt in 1923. What Trump really doesn't have is a pathological drive to dominate the nation motivated by extreme bigotry. Fascism is, of course, fairly amorphous and manifests itself in a way suitable to time and place; the key elements are authoritarianism, ultranationalism, and mythologised traditionalism. The US has longstanding tendencies towards all three, but has fortunately never quite fallen into the hands of leaders willing to strongly push for all three to the extent that the US became a fully fascist state. Still, the GOP has firmly established itself as a welcoming home for those who support police brutality, white nationalism, and enforced conformity to "traditional" values. As long as it remains politically profitable and they can daub a vaguely respectable face on it, the Republican party will not police itself. Vigilance for the emergence of fascist ideas in political discourse and pushing back against them is the duty of every citizen in a society that would like to call itself democratic.