"I happened to see a video of... presidential candidate Donald Trump at a rally. I saw him rouse the crowd to perform a loyalty oath... barely concealing the condescension for the crowd... I heard him talk about roughing up protesters and the media, and then.., "I could stand on 5th Avenue and shoot someone, and not lose any supporters." As a historian of authoritarian regimes... this was deeply familiar... This was a trial... to test the public, political elites and the press to see how... they would tolerate... extrajudiciality and violence. Authoritarians always tell you what they're going to do to you... [T]his is part of their politics of threat. Here was Donald Trump telling Americans... in January, 2016, that he approved of violent methods, could be violent himself, and considered himself above the law. The reactions..: a few expressions of incredulity... and a lot of "That's just Trump being Trump." ...Trump was following ...the authoritarian playbook, which most Americans ...were not familiar with. So I decided to educate people ...more than 60 op-eds ...[and] over 80 interviews to familiarize journalists with this ...analysis, and warn the public and decision-makers ...[P]ersonalist regimes..: the leader's personality.., obsessions.., quirks.., have an outsized influence over domestic and foreign policy. ...[H]is obsessions sometimes become state policy. Think of Hitler and the Jews... [T]he bad judgement caused by one of his worst character flaws, not wanting to take any criticism, can end... in ruinous situations and catastrophe for the nation, as... with Mussolini and Hitler... Trump is not fit to serve as leader... of American democracy, but he is... eminently fit to serve as the leader of an authoritarian state. ...[H]is impulsiveness, his mix of fragility and , ...his lack of empathy... and most disturbing, his willingness to... lead the country into ruin, to save his power and his source of personal enrichment, map 100%... on past authoritarian leaders' character[istics]. ...We have valuable knowledge to strike back, and yet, we haven't been doing it."