If any political pundit had said in 2012 that Mitt Romney would win the white vote by a 20-point margin over President Barack Obama and still lose the election, they might have been drummed out of the prediction business. But that’s what happened, and it signaled one of the most significant demographic shifts in U.S. history.

“In the first half of this century, minorities will be just as important as the baby boomers were in the last half of the 20th century,” says Brookings Institution demographer William Frey, the author of Diversity Explosion. “They are the future of our labor force and the future of our voting population.”

Almost half a century has passed since the Immigration and Nationality Act encouraged a wave of migration from Asia and Latin America in the ’70s, ’80s, and ’90s. That change in the makeup of the U.S. population has had consequences for everything from popular music to school curricula. According to the U.S. Census Bureau, children of minorities already outnumber non-Hispanic whites in more than a hundred U.S. cities. By the election of 2028, racial and ethnic minorities are expected to constitute a majority of adults ages 18 to 29 for the first time. By 2035, non-Hispanic whites will be outnumbered across all age groups.

“It will be very different from anything we’ve ever seen before,” says Frey. “Racial minorities were always a pretty small part of the population up until about 20 years ago, when we started getting more immigrants into the U.S. Minorities were mostly black, they were mostly living in segregated cities, they were out of the mainstream and out of people’s daily consciousness. That is no longer the case.”

According to the Pew Research Center’s analysis of census data, 78 counties in 19 states—from California to Kansas to North Carolina—have already shifted from being majority white to having no single racial or ethnic group in the majority.

People are also marrying across racial and ethnic lines as never before. According to the 2010 census, 15 percent of new marriages were between spouses of a different race or ethnicity, up from 6.7 percent in 1980. Frey expects this trend to continue, with significant social and political implications.

“In our history, race has been a sharp division of people all across the age structure, and all across the nation,” Frey says. “If we can open things up to having more interracial marriage, more people accepting each other as neighbors, that flares into politics as well.”

In the U.S., minorities typically lean liberal. According to a 2014 Pew Research poll, 64 percent of blacks identify as Democrats, and large majorities of Asians and Hispanics identify as either Democrats or Independents. Beyond the effect on presidential elections, an increase in minority voters could lead to changes in policy.

“A big message of what is going on in racial demographics is that people will come to realize that the next generation of young people need to have all of the access they can to a good education, to a good middle-class life, and that will take government support,” Frey says. “They need to have this assistance for all of us to succeed.”

Research by Jan Germen Janmaat at the University of London has found that ethnic diversity in the classroom actually leads to greater tolerance toward immigrants among teens, and Mark Hugo Lopez, the director of Hispanic research at the Pew Research Center, wonders whether the concept of diversity will even exist in 10 years.

“I do think that you might see something similar to attitudes about interracial marriages,” Lopez says. “In the 1960s and ’70s, there were many Americans who would say on a public-opinion survey that people of different races marrying each other is a bad thing for society. Boomers and Gen Xers would say it is a good thing for society. Millennials would say it really doesn’t make much of a difference.

“That’s where we may go with diversity—it may become so commonplace that people aren’t looking at each other wondering what their ethnic background and roots are. They’ll just see people as having different backgrounds and leave it at that.”

Next: The Many New Faces of the American Family