The story of the Republican Party in the Trump era is, by and large, one of a boiled frog.

President Donald Trump constantly pushed the envelope in ways that made his allies uncomfortable. They sometimes spoke out, especially early on, only to have the base stand by the president and rebuke them. That meant that when Trump pushed even further, his duly chastened allies increasingly responded accordingly: with silence. It’s how we got from a guy carping about supposed voter fraud in an election he won, in 2016, to a guy spurring a harebrained effort to overturn the 2020 election, which he lost.

The boiled frog (the proverbial tale of a frog that is boiled too slowly to realize what’s happening to it) is now returning, in the form of “replacement theory.” The GOP seems either unconscious of what’s happening — or doesn’t care.

As we wrote a while back, the Republican Party’s increasing embrace of replacement theory — the idea popular in white supremacist circles that immigrants are being brought in to replace native-born (read: White) Americans — has been a slow build. For years, it was an idea relegated to infrequent mentions by fringe Republicans who operated outside the political mainstream and weren’t generally welcomed in politer circles of the GOP. When it was mentioned, it was dressed up as something besides replacement theory, per se.

What has transpired over the past week, though, shows how quickly something can be injected into the bloodstream when that dressed-up version is initially given a pass. While some of the most prominent members of the conservative movement have increasingly espoused a version of replacement theory without calling it that — and sometimes seeking to differentiate it from the white supremacist version — they’re now just straight-up embracing the label.

The progression is, as it often has been on such things, best exemplified by Tucker Carlson.

Back in April, the Anti-Defamation League called for Carlson’s firing over a segment endorsing his version of replacement theory.

Carlson had said in a segment, “I know that the left and all the little gatekeepers on Twitter become literally hysterical if you use the term ‘replacement’ 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. Let’s just say it. That’s true.”

The letter drew a response from Fox News head Lachlan Murdoch, who maintained Carlson hadn’t actually endorsed replacement theory.

“Concerning the segment of ‘Tucker Carlson Tonight’ on April 8th, however, we respectfully disagree,” Murdoch told the ADL. “A full review of the guest interview indicates that Mr. Carlson decried and rejected replacement theory. As Mr. Carlson himself stated during the guest interview: ‘White replacement theory? No, no, this is a voting rights question.’ ”

Got it. So Carlson rejected replacement theory. He was talking about something else, even if it sounded a lot like replacement theory.

Except not so much anymore. Carlson last week doubled down and used the actual label favored by racist groups — “great replacement” — and more recently got some backup from a member of Congress, Rep. Matt Gaetz (R-Fla.).

As recently as July, Carlson was still suggesting that what he was talking about wasn’t replacement theory. While discussing President Biden’s supposed plan to “flood the United States with loyal new Democratic voters,” Carlson used his trademark scare-quote voice on replacement theory.

“ ‘The great replacement theory.’ ‘It’s a lie,’ they yelled,” Carlson said. “ ‘George Soros has nothing to do with that. Stop talking.’ ”

Even just last month, Carlson disputed the idea that what he was promoting was a “great replacement theory.”

“They tried to pull us off the air,” he said. “They said we were espousing something called the great replacement theory, a well-known racist fantasy. Right. In other words: Shut up.”

In a segment last week recapped by The Washington Post’s Philip Bump, though, Carlson explained that what Biden was doing was, in fact, not just replacement, but a great replacement.

“In political terms, this policy is called the great replacement, the replacement of legacy Americans with more obedient people from faraway countries,” Carlson said Wednesday.

Gaetz then sought to defend Carlson this weekend, stating that the Fox host was “CORRECT about Replacement Theory as he explains what is happening to America.”

So that’s two prominent figures on the right describing this as, in fact, “the great replacement” and “replacement theory.” And the former did so after his boss said he had “decried and rejected replacement theory.” This comes on top of certain congressional Republicans, including one who spoke to a group of white nationalists, floating the idea forming a caucus for which a draft document said immigrants were undercutting the “unique identity” of the country. (The idea was later shelved after an outcry.)

What’s notable here is both that they use these terms and also how sparsely they were used before. A Nexis search on Fox News transcripts indicates no mentions of “replacement theory” or the “great replacement” in this context before this year. Fox host Laura Ingraham was an early proponent of a version of this theory, but she avoided those terms.

It would certainly be understandable to rebut the claims made against oneself using the terms used by critics. And that’s what initially happened.

But more and more, those espousing this theory have just gone on and embraced the shorthand. Gaetz defended his Carlson defense Monday by arguing that even his use of “replacement theory” didn’t mean that replacement theory.

“The Left/Media think of replacement solely on race/ethnicity terms. I don’t at all,” he said. “Democrats failed the voters who relied on them to run their states/cities. Now they are importing new voters. That is my argument. Those reading more into it are projecting their own bias.”

Or perhaps the left/media are just citing the established meaning of a theory that has long borne the name Gaetz and Carlson chose to use. Gaetz and Carlson might say they’re trying to redefine it so it’s not about race or ethnicity, but Carlson made clear he felt Biden’s “great replacement” indeed involved injecting “non-White DNA” into our country, even though that’s not what Biden actually said.

Perhaps the best course is to use a different name, so as to avoid confusion. Unless, of course, your main goal is to troll — or you actually kind of agree with that original theory.