We have been seeing this change in popular culture and in higher education over the course of the last decades. Black and brown and Asian people sell you financial instruments and clothing. The president and first lady are black. Your college literature course includes Toni Morrison and Junot Díaz. But if you haven’t gone to college, where multiculturalism has been making its way for a generation, and if your version of America was formed in school in the 20th century, and that 20th-century image remains in your consciousness, you may have a lot to lose.

In our racially oriented American society, this change marks a demotion for white people. From assumed domination, they now take their place among the multiracial American millions. For Trump supporters embracing the social dimension of “Make America Great Again,” their vote enacted a visceral “No!” to multicultural America. As if to say, “Take us back to the time of unmarked whiteness and racially unmarked power” assumed to be white.

In the Trump administration, white men will be in charge (virtually his entire transition team, and practically every name offered for a potential cabinet post, is a white man). You could say that’s nothing new, that white men have been in charge forever. This is true, but now with a gigantic difference. This time the white men in charge will not simply happen to be white; they will be governing as white, as taking America back, back to before multiculturalism.

Mr. Trump’s presidential campaign’s leadership and support complicate making America great again, on account of the campaign’s tilt toward white nationalism. Here lies a snare that has entrapped white identity for decades. White nationalism scares many ordinary white people away from embracing whiteness, which white nationalism makes appear bigoted and terroristic. Given the people who emphasize their white racial identity — white nationalists, Nazis, Klansmen and so on — the white race is a spoiled identity. Embracing whiteness would seem to enmesh one in a history of slave-owning and all the discrimination flowing from it. What righteous person would want to embrace that? Up to now, there’s hardly been a pressing need to do so, for a fundamental dimension of white American identity has been individuality.

Conveniently, for most white Americans, being white has meant not having a racial identity. It means being and living and experiencing the world as an individual and not having to think about your race. It has meant being free of race. Some people are proud white nationalists, but probably not many of the millions who voted for Donald Trump. Thinking in terms of community would seem to be the job of black people. The Trump campaign has disrupted that easy freedom.