Tucker Carlson looks almost perplexed.

“You’ve heard a lot about the great replacement theory recently,” he tells his audience. “It’s everywhere in the last two days, and we’re still not sure exactly what it is.”

Wait a second. Hasn’t Carlson been one of the prime promoters of this theory?

The answer is yes. According to a count by CNN, Carlson has discussed the idea on his Fox News show at least 400 times.

Could he be backing away from the theory now that it has found its way into the manifesto of a self-described white supremacist, a teenager accused of slaughtering 10 people in a Buffalo grocery store?

Apparently not. On a program airing just days after the massacre, Carlson is pushing the theory again.

“Here’s what we do know for a fact,” he says. “There is a strong political component to the Democratic Party’s immigration policy. We’re not guessing this. We know this. And we know it because they have said so. They’ve said it again and again and again.”

In fact, he says, it’s really the Democrats who’ve been spreading this racist theory.

“They’ve written books on it and monographs and magazine articles,” he says. “They have bragged about it endlessly. They talk about it on cable news constantly. And they say, out loud, ‘We are doing this because it helps us to win elections.’ “That’s not something that’s said once. It’s something they’ve gloated about again and again and again. And we think that’s wrong.”

The show cuts to a clip of voting rights advocate Stacey Abrams.

“The Blue Wave is African-American,” she says. “It’s white. It’s Latino. It’s Asian-Pacific Islander. It is made up of those who are told that they are not worthy of being here. It is comprised of those who are documented and undocumented.”

Next comes Julian Castro talking about his home state of Texas moving from red to blue, followed by Dick Durbin, the No. 2 ranking Democrat in the U.S. Senate, discussing what he describes as a bad trend for Republicans.

And then there’s Joe Biden in a clip from February 2015 talking about a nonstop stream of immigrants that would soon leave white guys like him in a minority.

“That’s not a bad thing,” Biden stresses. “That’s a source of our strength.”

The camera comes back to Carlson, and he’s laughing.

“So you play clips of them saying it, and you’re the deranged conspiracy nut,” he says. “Maybe the funniest part is they may not be right.”

He doesn’t say where the Democrats might be wrong in their calculation. He just moves along to the heart of the so-called conspiracy.

“The Democratic Party has decided that rather than convince you, people who are born here, that their policies are helping you in making the country better and stronger, they will change the electorate,” he says. “Again, they say that. We are not guessing.”

Democrats do tend to embrace those words on the Statue of Liberty: “Give me your tired, your poor, your huddled masses yearning to breathe free.” They remember the ancestors who came to this country in pursuit of their own American dream.

Carlson clearly does not. “I know that the left and all the little gatekeepers on Twitter become literally hysterical if you use the term ‘replacement,’” he said on a show aired last spring, “if you suggest that the Democratic Party is trying to replace the current electorate, the voters now casting ballots, with new people, more obedient voters from the Third World.

“But they become hysterical because that’s what’s happening, actually.”

He couldn’t be more wrong. Democrats are not really transforming the electorate. The electorate is evolving, and Democrats are embracing the change.

Eventually, time will overtake guys like Carlson, and they’ll be left on the margins, along with their message of bigotry and hate.