Among whites casting ballots for Trump, 11.2 percent said support for immigration reduction was racist, a number that fell to 5.5 percent among white Trump voters without college degrees.

The gap between the most well-educated Clinton supporters and the least well-educated Trump supporters is stark — 91.3 percent to 5.5 percent. In other words, the very definition of racism is deeply contested.

Ashley Jardina, a political scientist at Duke, argues in her 2017 paper “The White Backlash to ‘Crying Racism’: How Whites Respond to Calling Racial Preferences Racist” that

Allegations of racism no longer work to reduce support for the target of the accusation. Instead, such accusations are now tantamount to ‘crying wolf’ and have the opposite of their intended effect — whites are subsequently more likely to express racially conservative policy preferences or to condone the target of the accusation.

According to Jardina, the

vast majority of white Americans who feel threatened by the country’s rising levels of racial and ethnic diversity are not members of the K.K.K. or neo-Nazis. They are much greater in number, and far more mainstream, than the white supremacists who protested in Virginia.

In response to a request to elaborate on her argument, Jardina emailed back:

I think it’s absolutely reasonable that many whites don’t think they hold racially prejudiced beliefs, even though by some social science measures, we think they do. Thus, when they’re accused of being “racist,” some whites either see the accusation as disingenuous, or they see it as a personal, unfounded attack, and they become defensive.

As a result, Jardina writes in her original paper, Trump “does potentially benefit from accusing his opponents of playing the race card.” The danger “of this new era, in which the new political strategy is to accuse elites of falsely making charges of racism,” Jardina argues,

is that it may be increasingly difficult, if not impossible, to effectively condemn politicians when they do in fact attempt to race bait, or when they express views that are racist or support policies that detrimental to racial and ethnic minorities.

Jeremy Peters captured this dynamic in his article in The Times last week, “As Critics Assail Trump, His Supporters Dig In Deeper.” Kaufmann, of the University of London, expanded upon Jardina’s work in his controversial paper, “ ‘Racial Self-Interest’ Is Not Racism,” writing that his survey data shows

that a majority of American and British people of all races believe that when the white majority seeks lower immigration to help maintain their population share, this is racially self-interested rather than racist behavior. This distinction is important because racism is a taboo, whereas ethnic self-interest, like individual self-interest, is viewed as normal.

These white conservatives

whose immigration stance is influenced by a desire to slow decline in their group’s share of the population rather than due to an irrational fear of outgroups, feel accused of racism. This breeds resentment.

Kaufmann contends that the racism charge has been a crucial factor in driving a rise in right-wing populism, in the United States and abroad:

Antiracist overreach on the immigration question arguably underlies the populist western backlash against elites. Cultural conservatives care deeply about the effects of immigration and resent being told their thoughts and voting behavior are racist. They hold elites responsible for enforcing antiracist norms — in the workplace, government and mainstream media — beyond the bounds of what they consider appropriate.

Kaufmann expanded on his views is an email:

I think liberal norm policing on immigration is a major contributing factor to right wing populism. Not directly, but indirectly. That is, by removing questions of immigration levels and cultural impact from the political conversation, it blocks the adjustment of political supply to political demand. A bit like prohibition of alcohol, the unmet demand opens a market opportunity for entrepreneurs.

Kaufmann cautioned, however, that this

is not to say mainstream parties should always supply market demand (i.e., segregation in the Deep South), but not doing so opens space for populism (i.e., George Wallace). So ultimately the question turns on whether the immigration taboo is morally justified.

Kaufmann and Jardina’s work raises a crucial question: has traditional polling failed to capture the actual views of the public on immigration? A number of experiments suggest that many people feel social pressure to conform to “social desirability” expectations and to mask their opposition to immigration.

Alexander Janus, a sociologist at the University of Edinburgh, told me that his own and other studies “suggest that polls substantially underestimate the true extent of opposition to immigration due to social desirability bias.” Janus specifically pointed to Gallup surveys that appear to illustrate a steady liberal trend in views toward immigration.

According to Gallup, the share of voters who say immigration levels should be reduced fell from 65 percent in 1995 to 35 percent in 2017. The share saying immigration should be increased rose from 7 to 24 percent, and the share who think immigration levels should remain unchanged rose from 27 to 38 percent over the same period. Of course, this could just reflect increased public support for immigration.

But scholars have attempted to test the reliability of poll results like these. In a 2010 paper, “The Influence of Social Desirability Pressures on Expressed Immigration Attitudes,” Janus described a survey experiment designed to elicit anti-immigrant views without forcing participants to explicitly state their opinions. (The design of the experiment is complex, and readers should open the link to examine the details.)