He REALLY isn't. He can barely speak a coherent sentence and somehow the party of homophobia is cool with a guy who can only dance by miming a blowbang.

There are two big keys to his success and they are true of many populist leaders:

1. His support base know they are as dumb as he is, if not dumber, and are glad they have a leader who won't use big words like "because".
2. The vast majority of people never see him. They see a highly edited clip on tiktok or just hear that he said they should beat a trans person on Facebook and so forth.

Contrast that with someone like Big Daddy Z. "I would love to visit but we are too busy destroying it" really isn't anything new and there are countless quotes along those lines from WW2 and the like. But he has basic people skills, a great smile, and knows how to sound like a human being where "I might not always agree with you but I would totally share a drink". And it works. It belittles the opposition, reminds people of Ukraine's current accomplishments, and makes you like the guy.

That is charisma.

Other people are disagreeing, since he's not really smooth the way the term implies. But, maybe he has a different kind. Charisma is hard to define.

Trumpism predated Trump, though. He was just the first rich guy willing to openly say horrible things in the primary.

It isn't charisma, it is convenience. The convenience to be an asshole without repercussion, is what Trump promises. His backers want to become Trump.