This is an adapted excerpt from the Oct 15 Episode of “All In with Chris Hayes.”

Eight decades ago, the United States joined an alliance of nations in a world war to defeat fascism. Millions of Americans fought and sacrificed for this war, including the father and mother of retired General Mark Milley. In 2019, Milley would become chairman of the Joint Chiefs of Staff, the highest-ranking general in the U.S. military.

Decades after his parents' military service, Milley warns urgently that fascism is once again spreading, not in Germany or Italy, but here in America. According to Milley, as journalist Bob Woodward reports in his upcoming book, the biggest threat to democracy and security in the country is the 45th president and the same man who wants to become the 47th president: Donald Trump:

Less than three weeks before Election Day, the former top general is warning America that it could elect a fascist as president. And he's right: Trump is running a clearly fascist election campaign.

It is becoming increasingly difficult to ignore as threats of violence and racism become a central feature of his rhetoric and rallies. That was evident this week when Trump decided to hold a key rally not in a battleground state but in the heart of blue Colorado, in the Denver suburb of Aurora.

In Aurora, Trump and his vice presidential candidate, Senator JD Vance, have been spreading the false narrative for weeks that the city is paralyzed by migrant gangs. To put it bluntly: it's a bigoted lie. Just as false and racist as Trump's claims about the Haitians in Springfield, Ohio. And just like in Springfield, local Republicans, including Aurora's Republican mayor, are denouncing Trump's lies.

But that hasn't stopped Trump and his campaign from using the city to make their vile, dishonest arguments, claiming that America is “occupied” and needs to be “liberated.” At the rally, Trump brought fascism to the extreme, ramped up racist hatred of migrants and promised to mobilize the federal government to use violence against them.

“Kamala imported an army of illegal immigrants, gang members and migrant criminals from Third World dungeons,” Trump falsely claimed. “Today I am announcing that once I take office, we will conduct a federal Operation Aurora to accelerate the elimination of these brutal gangs. And I will call the alien Enemies Act of 1798.”

Yes, the Alien Enemies Act. Trump is promising to “round up” migrants using a law passed under John Adams that would allow the president to arrest, detain and deport “aliens” from any country at war with the United States.

Woodrow Wilson invoked it to expel the Germans in World War I and led to the U.S. internment of Japanese Americans in World War II. It is a disgusting stain on the history of American pluralistic democracy and Trump wants to use it to round up people on American streets.

And if you think that you're safe because you're not an immigrant and that Trump would never use that power against you, think again:

“I think the bigger problem is the people on the inside,” Trump told Fox News on Sunday. “We have some very bad people. We have some sick people, radical left-wing lunatics… and if necessary, the National Guard, or if it's really necessary, the military, should be able to solve the problem easily, because they can't let that happen.”

The fascist doctrinal idea is that if you resist, you, your neighbors, and your family could be classified as domestic enemies of the state, more dangerous than a foreign enemy. This is the campaign that Trump is running for president. The only way to become more fascist is to portray Democrats as unworthy, morally degenerate people.

Oh, wait. The Trump campaign is doing just that, running sweeping ads in swing states accusing Harris of supporting “taxpayer-funded gender reassignment surgery for prisoners and illegal immigrants” and telling Americans, “Kamala is for she/her .”President Trump is for you.” Trump is running this ad because he believes fear and bigotry will win them the election.

This is a fascist campaign: it is a war against the truth and against the people who tell the truth. It promises a violent final victory over any perceived enemy of Trump – using the power of the state and relying on the voice of the people.

And he is tied in the polls with the incumbent Democratic vice president. Why is that?

For one thing, after decades of right-wing media programming, many Americans are prepared for an authoritarian leader. Part of the country just likes the strongman pitch in a positive way. Of course, things rarely work out for them in the long run. Survivors of fascist regimes are proof that no supporter is safe from the regime they support.

But the second and crucial advantage that fascism has in America today is that the press still doesn't know how to fully communicate the dangerousness of our situation – in part because Trump is the world's most famous liar. He is such a liar that even many of his biggest supporters simply believe he would never do the things he says. As one Republican pollster told the New York Times this week, “The normal rules simply don't apply to Donald Trump, and you've seen that time and time again.”

This pollster said that his polls and focus groups found that “people think he says things for effectiveness, that he blusters because that's part of what he does, his shtick.” They don't actually believe it will happen.”

But the question of whether or not Trump should be taken seriously received a definitive answer in his final weeks in office as he desperately tried to hold on to power.

Ahead of that election, conservative columnist Ross Douthat wrote that “there would be no Trump coup,” adding that Trump was “a loud-mouthed weakling, not an aspiring autocrat.”

Trump's former chief of staff Mick Mulvaney wrote: “If Trump loses, he will concede gracefully… He will fight hard to ensure the results are fair, and in the end he will accept the result, whatever it is.”

We now know how fatally wrong those assumptions were. But even as Trump ratchets up the fascist rhetoric, we forget what he did as president and deny what he would do if he were president again.