Martin Amis has suggested that Donald Trump, who the author speculated could be suffering from dementia, is preparing for the possibility of an untimely end to his presidency by “trying to stock up an army of neo-Nazis”.

Comparisons between Trump and Hitler are wrong, Amis argues, because the US president actually resembles a different fascist: Hitler’s ally Mussolini. Speaking to Guardian Weekend in New York, the novelist recalled seeing the slogan “Mussolini Is Always Right” on Italian bridges in the 1970s.

“Trump is that crazy, and that boastful, and that deluded,” Amis said. “Even Mussolini had a few good years before he lost it. But people like Hitler and Stalin wanted to change human nature. That’s what totalitarianism is. Trump doesn’t want to make a total claim on you as an individual. He wants to stay in power, and that’s about it.”

According to Amis, the president is cannily exploiting the fears of America’s far right. “Trump is trying to stock up an army of neo-Nazis who, if he gets ousted before his term is over, are going to think it’s a coup. They’ve all got huge guns; that’s a sword to hold over the situation. That’s what they’re scared of,” he said. He characterised such supporters as the kind of man who “before 2008 could look out of his trailer and say: ‘I may not be much, but I’m better than a black man.’ Then they see Obama, so handsome and witty and learned, and think: ‘Can I really say that?’”

In a wide-ranging interview about his forthcoming book of essays, The Rub of Time, in which he spoke about everything from the “stupefying effect” of the internet to the fact that he has never looked at social media, Amis compared the day after the US election to Germany after Hitler’s appointment as German chancellor in 1933, citing the German historian Sebastian Haffner. “He said the feeling was not of horror; it was of complete unreality. You go out into the street and people look different. The commerce, the cars; it all looks staged for your benefit. Completely make-believe. A sick-making feeling. And here it is. And what the fuck did they expect?”

Trump himself, according to Amis, has changed significantly over the past decades, a change that the author suggested could be attributed to dementia. “If you look at old tapes of him on [US talk show] Charlie Rose, he’s using words like ‘chagrin’ correctly. And with a certain amount of ironic reserve,” he said.

Amis, the British author of acclaimed novels including Money, London Fields and The Zone of Interest, moved to New York in 2011, saying at the time that the UK was in a condition of “moral decrepitude” and that he “would prefer not to be English”.

His feelings about his native country are warmer now, and he revealed that he plans to move back one day. “I miss the English … I miss Londoners. I miss the wit,” he told the Guardian. “Americans aren’t as witty as Brits, because humour is about giving a little bit of offence. It’s an assertion of intellectual superiority. Americans are just as friendly and tolerant as Londoners, but they flinch from mocking someone’s background or education.”

An experienced controversialist, the novelist’s pronouncements have provoked debate over race, religion and gender politics. In 2007, the critic Terry Eagleton accused him of holding views worthy of a “British National Party thug”, while three years later the journalist Anna Ford suggested his attitude to women was “highly questionable”. In 2015, Amis wrote an essay slamming Jeremy Corbyn as “incurious”, “humourless” and “undereducated”. But despite Labour’s success in June’s general election, the writer has not warmed to the leader.

“Two E grades at A-level. That’s it. He certainly has no autodidact streak. I mean, is he a reader?” he said, adding that Corbyn is “more cautious now, but still grimly ideological, and an admirer of tyrants – Chávez, Putin”.

As for Trump, Amis is not hopeful that the US president will be impeached, but suggested that looming international events could reveal him to onlookers. “I am, in a way, thirsty for an international crisis,” he said. “Not with North Korea; he’s itching to do that and thinks he’ll get the Nobel peace prize if he wipes it off the map. But I want something really ticklish, like the hostage crisis after the Iranian revolution, where he’s not going to reach for the button, but people are going to see him under stress.”