Washington did pay attention. In the mid-1990s, with Republicans in control of Congress and President Clinton tacking more to the right, tougher immigration policies took shape. Fences were built and patrols stepped up. Deportations rose. “They were scared to death of what Prop 187 symbolized,” Roberto Suro, a professor of public policy and journalism at the University of Southern California and former New York Times journalist, told Retro Report. The greater aggressiveness of the 1990s, he said, created “the basis for the large-scale removals that we’ve experienced in this country for the last 10 years.” Those removals reached a peak under President Barack Obama, described disapprovingly by some critics as the deporter-in-chief.

Now here is Mr. Trump, who built his presidential run on a promise to build a border wall, and who began his campaign by attacking Mexico as supposedly an exporter of rapists and other criminals. As in 1994 California, the anger is directed powerfully at those arriving without documentation. Last month, though suggesting he was open to compromise, the president announced he would end Deferred Action for Childhood Arrivals, or DACA, the Obama-era program that protected immigrants who were brought to this country illegally as children.

The Trump assault, however, extends to all forms of immigration. In August, he embraced proposals to cut lawful entries in half over the next decade. Preference would be given to people possessing special skills and higher education — hardly the tired, the poor and the wretched refuse embraced in “The New Colossus,” the Emma Lazarus poem affixed to Miss Liberty’s base.

Two weeks ago, Trump administration officials disclosed their intention to cap refugee admissions at 45,000 over the next year. That would be the lowest ceiling, by far, since a 1980 law gave the president authority to help set limits on those searching for a haven from persecution in their own countries.

Surveys show that Mr. Trump’s “America first” sloganeering helped him eke out victories in November in critical swing states like Michigan, Pennsylvania and Wisconsin, where some longer-term residents are uncomfortable with rising numbers of Latino newcomers. Sudden diversity is rarely simple. For some, it is scary.

But California in the wake of Proposition 187 may point to where the country as a whole is headed. The most populous state has undergone a profound demographic shift since the mid-1990s. Latinos now have a plurality; they and Asian-Americans combined are the majority. Non-Hispanic whites account for less than 40 percent.

As the video shows, Latinos in California are registering to vote in ever larger numbers, though whites are still more likely to go to the polls. The Latino representation in the legislature grows as well, to include prominent figures like State Senator Kevin de León. He said that many Californians, and not just Latinos, have had “enough with the scapegoating” of certain ethnic groups whenever the state has economic or other troubles.

Now California is cerulean blue politically, and there lies a cautionary tale for Republicans. With demographics changing almost everywhere, they may yet find that the short-term gain of the Trump 2016 victory comes at their long-term expense.

Still, dispelling xenophobia is no easy matter: “Immigration is one of those touchy issues for Americans that can suddenly turn ugly and flower into a major national argument.” That was from Charles Wheeler, speaking in 1994 as executive director of the National Center on Immigrant Rights. What he said then remains true today.

CLYDE HABERMAN, a regular contributor to Retro Report, has been a reporter, columnist and editorial writer for The New York Times, where he spent nearly 13 years based in Tokyo, Rome and Jerusalem. Subscribe to our newsletter here and follow us on Twitter @RetroReport.

This article first appeared in The New York Times.