Donald Trump has spent virtually all of his nine years in politics stoking cultural resentment by using hyperbolic and false claims about scourges of immigrants and the crimes they commit. He has gradually worked his way up to the idea that immigrants are “poisoning the blood” of the country — an echo of historical fascism — and a more recent promise to deport legal Haitian migrants whom he falsely accused of stealing and eating people’s pets in Springfield, Ohio.

On Wednesday came a striking example of how much the American political right has latched on to this brand of resentment and nativism.

A new CNN poll showed that a majority of the Republican Party now agrees that “an increasing number of people of many different races, ethnic groups, and nationalities in the U.S.” is mostly threatening (55 percent) rather than enriching (45 percent) to American culture.

This represents a sharp rise from 2019, when just 21 percent of Republicans said that this increasing racial and ethnic diversity was threatening. Back then, Republicans said by a 48-point margin that it was actually more enriching than threatening.

It’s also up significantly even from just last year. A CNN poll in March 2023 found 41 percent of Republicans viewed this increasing diversity as threatening.

So, from 21 percent in 2019, to 41 percent last year, to 55 percent today.

Over the span, there’s also been a rise in this sentiment among independents — from 11 percent in 2019 to 32 percent today. But that appears to owe mostly to Republican-leaning ones. The percentage of Democratic-leaning voters (including independents) who embrace the idea that this diversity is threatening to American culture has ticked up only slightly, from 6 percent to 13 percent. Democrats only have gone from 7 to 11 percent. And 86 percent of Democratic-leaning voters continue to say that this form of diversity is mostly enriching.

This is far from the only evidence of increasing anti-immigrant and anti-diversity sentiment. Americans as a whole have become more anti-immigration, as we’ve seen record-high illegal border crossings in recent years (numbers that have dropped precipitously lately). A poll earlier this year showed 8 in 10 Republicans and nearly half of Americans overall agreed that undocumented immigrants were “poisoning the blood” of the country. Republicans in particular have rallied to the debunked claim that immigrants commit more crime than native-born Americans, and Americans have rallied to Trump’s concept of mass deportation.

Trump’s presidency was actually a remarkably good time for pro-immigrant sentiment, despite his rhetoric. But things have shifted overwhelmingly since then.

What’s particularly striking about these new numbers, though, is that they aren’t just about undocumented immigrants or crime; they’re about diversity more broadly and American culture. They’re about people from other places and with other backgrounds supposedly coming in and harming American identity. Call it “poisoning the blood” or something else; the Republican Party has gradually come to adopt it, after years of Trump upping the ante.

George W. Bush was a Republican president who, whatever his faults, took care to tamp down this form of resentment. After the terrorist attacks of Sept. 11, 2001, he encouraged Americans not to paint Islam with too broad a brush, playing up the contributions of Muslims to American society and identity.

By 2021, Bush seemed to sense where his party was headed. In a rare interview with NBC News, he said the Republican Party was “isolationist, protectionist and, to a certain extent, nativist.”

Three years later, he can probably drop the “to a certain extent.” The nativists have apparently taken over.