John Kelly, Donald Trump’s longest-service chief of staff, made dire warnings Tuesday about what could happen if his former boss wins back the White House, and confirmed disturbing comments the former president allegedly made about Adolf Hitler.

Kelly, a former Marine general who also served as Trump’s homeland security secretary, spoke to both The Atlantic and The New York Times about his concerns, saying he was motivated to go on the record after Trump suggested he’d use military force against his domestic political enemies.

Trump meets the definition of a fascist and would govern like a dictator, Kelly warned, telling the Times that Trump “never accepted the fact that he wasn’t the most powerful man in the world — and by power, I mean an ability to do anything he wanted, anytime he wanted.”

The retired general pointed to the definition of a fascism ― a government with a “dictatorial leader, centralized autocracy, militarism, forcible suppression of opposition, belief in a natural social hierarchy ― and said that from his experience working with Trump, “those are the kinds of things that he thinks would work better in terms of running America.”

As Trump’s chief of staff, Kelly spent more time behind closed doors with the former president than nearly anyone else who worked in his administration.

Speaking to The Atlantic’s Jeffrey Goldberg, Kelly also confirmed an incident first divulged in a 2022 book, in which Trump reportedly asked Kelly, “Why can’t you be like the German generals?” and claimed Hitler’s generals “were totally loyal to him.”

Here’s Kelly’s confirmation, according to Goldberg:

This week, I asked Kelly about their exchange. He told me that when Trump raised the subject of “German generals,” Kelly responded by asking, “Do you mean Bismarck’s generals?” He went on: “I mean, I knew he didn’t know who Bismarck was, or about the Franco-Prussian War. I said, “Do you mean the kaiser’s generals? Surely you can’t mean Hitler’s generals?” And he said, “Yeah, yeah, Hitler’s generals.” I explained to him that Rommel had to commit suicide after taking part in a plot against Hitler. Kelly told me Trump was not acquainted with Rommel.

Trump’s spokespeople have repeatedly denied such a conversation ever happened.

Kelly also confirmed previous reporting about Trump praising Hitler, telling the Times that “more than once,” Trump told him: “You know, Hitler did some good things, too.”

Trump’s recent comments about using the military against “the enemy within” are similar to remarks he made while in office, Kelly told the Times, saying he repeatedly had to inform Trump that he did not have the authority to use the military against Americans. Overall, Kelly said, Trump showed very little respect for or understanding of the Constitution, American democracy or the concept of rule of law.

Kamala Harris’ campaign urged voters to listen to Kelly’s warnings.

“The people who know him best are telling us Trump is unhinged and pursuing unchecked power that would put us all at risk,” spokesperson Ian Sams said in a statement. “We should all listen.”

Kelly told the Times he wasn’t endorsing any candidate and said that he still agrees with Trump on some of his policies. However, he warned, “It’s a very dangerous thing to have the wrong person elected to high office.”

The Atlantic piece included other damning details about the former president, including one incident in which Trump reneged on his offer to pay for a slain service member’s funeral.

“It doesn’t cost 60,000 bucks to bury a fucking Mexican!” Trump allegedly said when he found out the cost, according to witnesses in the room at the time. The funeral was for Vanessa Guillén, a 20-year-old Army private and daughter of Mexican immigrants who was bludgeoned to death by a fellow soldier in April 2020.

“Don’t pay it!” Trump allegedly ordered his chief of staff at the time, Mark Meadows. He reportedly brought it up again throughout the day, saying: “Can you believe it? Fucking people, trying to rip me off.”

A Trump spokesperson denied the story.