Ok me too. To flesh out the 'literally hitler' side of things. I don't think he really is Hitler, since there was only one and it's grounded in history. I would compare maybe to Estado Novo, one of the weird other implementations of authoritarianism, that had a slightly different method, stayed out of the war, and lasted until 1974.
The early Fascists had a lot of odd specifics, like using mythology to get that nostalgic feeling. Again that's grounded in history, but while it was part of their method, modern research has shown it doesn't stand on its own when tested separately on people. It's not at the core of whatever 'it' is, but the research did find a more tightly linked core. Trump's approach is consistent with the modern research rather than old methods.
The modern theory is a story of demographics and leadership. There are many more followers than dictators, so they started there. I know it's mired in politics -- but there is a real question, 'how can so many follow a dictator', that has to be answered in psychology and assessed on demographics. If you can excuse imperfect methods on an important topic, they actually have found a bunch of stuff.
The RWA scale describes the followers. I think loyalist is a better term than authoritarian, again a loaded term. Loyalist has the connotation of a tightly knit group with suspicion of outsiders, which is the clearest description of the individuals. It's found in every population, every demographic; it's random between gender, increases slightly with age and with parenthood, correlates at 0.5 between parent and child, doesn't correlate with voting. [1]
I have to emphasize it doesn't mean conservative (and I apologize for the name, 'right wing' means something different in psychology): when it was made, RWA scores were almost random between parties, which would be a poor result if it was supposed to measure conservatives. Also, they're not bad: high RWAs are 10% of any population, and they don't get in any trouble, most of the time.
The SDO scale describes the leaders. They crave power and inequality, with a good dose of narcissism. They are amoral, and they have a different perspective on 'truth' than normal people. RWAs lie sometimes, they're about like other people that way. SDOs don't even care if what they say is true, they say it for the effect it has on others. It's relevant that Trump uses lies so often. They promise, threaten, flatter, and yes even lie to get what they want. They are perfectly suited to say anything to take over a loyalist group, and they crave followers.
(Like when Trump said he would do war crimes... Fox asked, "The military said it would refuse your illegal orders?" "Believe me, they'll follow my orders" cheers "But, that's illegal?" "Believe me, they will" cheers. He was just playing it up for the machismo, he said the next day he didn't mean it 'literally', but that's the kind of untrue statement made for applause that illustrates it. link)
Supposing you wanted to use this knowledge for evil to start a new political party, the tools available now are much better than the Fascists had. Psychology and polling data, both with reams of data at p<.05, give much better prediction of how to make the perfect sales pitch.
First, he's doing it at the perfect time. RWA score used to be random between parties... 20 years ago. With a religious party to act as a magnet, it's been slowly accumulating the loyalists to one side. RWA has a different culture in different places, but the US version has a lot to do with religion. Not to say 'religious people are authoritarian'; 80% are religious and only 10% are high RWA. But those who are high RWA will naturally think of religion as 'their side', and will inexorably draw to that party. Measured from polling, RWA distribution is more polarized than ever, even more than in 2012 when he floated the Birther test balloon. (I think if Trump needs an -ism, it should be Birtherism: it connotes the tightly knit and suspicious of outsiders demographic that is important in this, as well as the US meaning of it.) These are the best conditions in maybe 10 elections. [2]
Second, assessed from polling data, high RWAs have different priorities than the wider GOP, and Trump has taken the perfect position on each issue where they differ. Furthermore, that's all he talks about. He's dropped all the planks of the GOP platform they don't care about. He talks first about what they most want to hear. That's the reason for 'the wall' -- I think it's a poor investment like GisterMizard but I don't think the purpose is for his legacy. The purpose of setting it as a priority is to define a political stance, a wedge issue which splits the republican base along loyalist lines. Which also explains the winning. The odds of choosing the right positions on that subset of issues are maybe 1 in 100.
So combining the odds, 1 in 10 for the right time, 1 in 100 for the right message, 1 in 10 for the personality, the odds are 10000 to 1 that all the pieces would fit so well. Let's dispel the notion that he doesn't know what he's doing. Trump's approach is not extreme, so not Hitler, but the point is how closely it aligns to every criteria. Trump is a newly invented, focus group authoritarianism. "A kinder gentler machine gun hand", is a line from a song he used on campaign.
So, a mix of sauces:
1 A long and rambling pdf all about the research. Page 166-197 describes the interraction between RWA and SDO, which is at the core of it. More than other politics, it's defined by group dynamics between followers and leader.
2 Description of the demographic now, and how Trump matches their policy rather than the GOP average. Compare to page 209 of the pdf, showing correlation between politician RWA and their voting record.
3 Another overview of the two types, with a description of the autocrat 'persona' that always seems to step in to place. It sounds just like Trump, which is subjective, but just to point out it also walks like a duck and talks like a duck.
4 Umberto Eco's essay is often quoted as a definition of Fascism. Using a completely different method than RWA, he made a 14 point distillation of what the different historical implementations had in common. Trump is not 'slightly' like this -- he matches all 14, like he's using it to write speeches. The odds from that separate test are about 16000 to 1.