The most important word in Donald Trump’s lexicon may be: “again.”

The word anchors many of his signature declarations, as when he insists: “If I’m elected president, we will win again.” In a jab at the secularization of American life, he’s promised: “If I’m elected … we’re all going to be saying ‘Merry Christmas’ again.” And of course, the word is the exclamation point on his trademark pledge to “make America great again.”

In the Trump vocabulary, the word “back” ranks closely behind “again.” Trump is forever promising to “bring back” things that have been lost. Manufacturing jobs, steel and coal production, waterboarding of terrorists, “law and order” in the cities—all of these Trump says he will “bring back” to reverse what he portrays as years of American decline.

These phrases capture the mission of restoration underpinning Trump’s campaign. They touch the pervasive sense of loss among many of his supporters—the belief that the changes molding modern America have marginalized them economically, demographically, and culturally. These words allow him to evoke a hazy earlier time when American life worked better for the overwhelmingly white, heavily blue-collar coalition now drawn to him. And they help explain the visceral connection he has established with those white working-class voters, a connection strong enough to survive a concatenation of controversies that might have exploded any other candidate.

“It’s a visceral feeling of being left behind,” said Daniel Cox, the research director of the non-partisan Public Religion Research Institute, which studies cultural attitudes. “Economically they are being left behind, but culturally, too, things that seemed to be O.K. when some of these folks were younger—whether it’s the words you can use or approaches to gender roles—are no longer O.K.”

Yet if Trump’s mission of restoration has deepened his support, it has also imposed a restrictive boundary around it. The growing groups long eclipsed in American life have no idealized past moment they are longing to restore. A young Hispanic lawyer or middle-aged professional woman might not think they are treated equally today, but few are likely to believe people like them enjoyed more opportunities decades ago. The same is true for other racial and religious minorities, gays, and transgender people. For all of these groups, the past that Trump evokes is one that kept them subordinate, in the shadows, or worse.

“It’s almost a cultural nostalgia, for when white male culture [was] most dominant,” the Democratic pollster Cornell Belcher said. “When African American and Hispanic voters hear that … they get the joke that going back to the past [would be] great for some but at the expense of others.”

In that way, Trump’s persistent promises to “bring back” an earlier America seem certain to deepen a shift from class to culture as America’s central political divide. As I’ve written, Democrats now represent a coalition of transformation (revolving around minorities, Millennials, and college-educated whites, especially women) largely comfortable with demographic and cultural change. In turn, Republicans champion a competing coalition of restoration largely uneasy with these changes (built mostly on blue-collar, older, religious and non-urban whites).

With his signature proposals to build a border wall, deport 11 million undocumented immigrants, and to temporarily ban Muslim immigration, and with his spirited defense of police against “black lives matter” protesters, Trump has aligned unreservedly with the priorities of the voters most anxious about demographic change. On cultural change, he’s a more ambivalent general. His language about women has caused many of them to question whether he views them as true equals (though many in his companies defend his record on promoting them). But on issues relating to the sexual revolution—from abortion to gay marriage to transgender rights—his commitment to traditional conservative positions is recent and uncertain.

Yet Trump’s overall message and positioning appears destined to harden these cultural divides, particularly among whites. The first national polls pitting Trump against Hillary Clinton have shown him leading big among the same non-college educated white voters who keyed his nomination victory. Yet the same surveys consistently show her running even or ahead among college-educated white voters—which no Democratic presidential candidate has carried in polling since 1952. Given the Democratic strength among minority voters, if Clinton actually finishes that well with white-collar whites, Trump almost certainly couldn’t win.

The pattern of white support for Trump and Clinton precisely tracks the reactions to social and demographic change evident in a national PRRI/The Atlantic Poll this spring. Those whites who’d obtained a high school degree or less backed the conservative position on every policy and cultural dynamic the poll measured to a significantly greater extent than those with at least a four-year college degree. This was true on issues ranging from immigration, to the Muslim ban, to whether government pays too much attention to minorities, and whether society is better off when men and women follow traditional gender roles. Recent NBC/Wall Street Journal polling on transgender rights found the same split.

Though many African Americans and Hispanics also hold culturally traditional views on questions like these, Trump’s polarizing posture on racially tinged issues (like immigration and crime) seems certain to limit his support among them. Trump begins the general election strongly positioned for debates against a weakened Clinton about the economy, security, and changing Washington. But by defining himself so indelibly as a candidate of cultural restoration, he risks that the Democratic coalition of transformation which has won the popular vote in five of the past six presidential elections will mobilize against him in large enough numbers to deny the Republican Party the White House—again.