A girl participates in a protest calling for businesses to sever their relationships with Donald Trump over his recent comments about Mexican immigrants as they demonstrate outside the site of a new hotel owned by Trump at the Old Post Office Building in Washington on July 9.Yuri Gripas / Reuters

What do NBC and ESPN’s decision to cut ties with Donald Trump in retaliation for his comments about Mexican immigrants, the South Carolina House’s vote to take down the Confederate flag, and a Harrisburg newspaper’s decision to “very strictly limit” letters and op-eds opposing same-sex marriage have in common? They’re all signs of a historic shift: Political views that were once controversial are now unacceptable.

We’ve seen such shifts before. Until the 1960s, supporting legal segregation of the races was a respectable position among both conservative Democrats and Republicans, and was championed by such intellectual eminences as William F. Buckley. After Congress passed the civil- and voting-rights acts, it no longer was. Until the 1980s, prominent conservatives defended apartheid South Africa as a staunch U.S. ally besieged by Nelson Mandela’s African National Congress, which the Reagan administration classified as a terrorist group. After apartheid ended, Mandela became the equivalent of Martin Luther King, a man revered by left and right alike.

It’s not just conservatives who have been forced to abandon once mainstream opinions in the wake of political and cultural change. In the 1930s, prominent progressive intellectuals and artists spoke admiringly about communism and the Soviet Union. Once the Cold War dawned in the late 1940s, such views cost some of them their jobs. In the 1960s, some New Left thinkers and activists denounced monogamy and organized religion—and condemned not just the Vietnam War, but anti-communism itself. By the more culturally conservative 1980s, such views were confined to an academic fringe.

What creates such change? Obviously, part of it is electoral reality. In 1948, Henry Wallace tested the proposition that a candidate who had accepted the Communist Party’s endorsement could attract widespread support. He won 2.4 percent of the vote. In 1972, George McGovern tested the proposition that America would embrace a candidate who called for ending not merely the Vietnam War, but the Cold War itself. He won a single state.

That’s part of what’s happening in the Republican Party now. GOP elites are pushing back against Donald Trump because the 2008 and 2012 elections taught them that demonizing Mexican immigrants is political death.

But such shifts aren’t only political. The Republican South Carolina legislators voting to take down the Confederate flag aren’t doing so because they fear losing their seats. NASCAR and the PGA aren’t cutting ties with Trump because they’re worried about the GOP’s fortunes in 2016.

Politicians alone can’t render a once-acceptable opinion beyond the pale. They need allies in the cultural and economic sphere. It wasn’t only Harry Truman who defeated Henry Wallace and the pro-Soviet left. In the late 1940s, some of America’s most important intellectuals—men like Arthur Schlesinger Jr. and Reinhold Niebuhr—began arguing that communism was as anathema to liberalism as was fascism. In the early 1970s, it wasn’t only Democratic bosses like Chicago mayor Richard J. Daley who loathed McGovern. An entire community of intellectuals—the early “neoconservatives”—revolted against McGovernism. Some of these intellectuals, like Irving Kristol and Norman Podhoretz, migrated to the political right. But others, like Daniel Bell, Daniel Patrick Moynihan, and Nathan Glazer, remained on the left. In the 1980s, they were joined by The New Republic and the Democratic Leadership Council, institutions that waged a successful intellectual campaign to make McGovernism unacceptable on the mainstream left.

If cultural elites helped render certain left-wing views unacceptable in the 1940s, 1970s, and 1980s, economic elites are helping render certain right-wing views unacceptable today. David Brooks foresaw this phenomenon fifteen years ago when he wrote Bobos in Paradise, arguing that corporate America was embracing the liberal-cultural ethos of the 1960s. In 2003, Intel, Merck, and Boeing all filed briefs urging the Supreme Court to uphold affirmative action in college admissions. Earlier this year, Goldman Sachs, Google, and Coca-Cola urged the Court to legalize same-sex marriage. In South Carolina, the state’s chamber of commerce and manufacturer’s association lobbied Governor Nikki Haley to remove the Confederate flag. And since Trump’s comments about undocumented Mexican immigrants, he’s faced harsher retribution from many of the corporations he does business with than from the Republicans he’s running against. If Democratic Party leaders once needed liberal intellectuals to marginalize Wallace and McGovern’s views about communism, Republican leaders need corporate America to marginalize the anti-gay rights, anti-Mexican, pro-Confederate flag wing of their party today.

Eventually, they’ll probably succeed. By 2020, it’s hard to imagine a Republican nominee who doesn’t back gay marriage, comprehensive immigration reform, and an end to government displays of the Confederate flag.

So what happens to the millions of Americans who have suddenly found their views deemed beyond the pale by America’s political, economic, and cultural elites? If history is any guide, they’ll go underground. In the late 1940s and 1950s, the Old Left that had sympathized with the USSR crumbled. But a clandestine-radical tradition remained. And when the New Left erupted during Vietnam, it included many “red-diaper” babies—children from families that, quietly, had always opposed the Cold War. Something similar happened after the invasion of Iraq, when a new generation of progressive “netroots” activists began looking admiringly at the McGovernites who had turned the Democratic Party against the Vietnam War.

Opposition to same-sex marriage, crude attacks on Mexican immigrants, and support for the Confederate flag may be growing less acceptable. But the political tradition that underpins those views will remain, and in unpredictable ways, it will adapt to 21st-century demographics. For a glimpse into that future, just look at Bobby Jindal, an Indian American, Hindu-born Rhodes Scholar who is running against hyphenated Americanism and suggesting that the Supreme Court be abolished for contradicting the Bible.

Sooner or later, political upheaval will spark new movements aimed at distinguishing between those Americans who deserve equal citizenship and those who don’t. And as Jindal’s career suggests, these movements may prove more multicultural than we can today imagine. I don’t look forward to the return to political acceptability of forces aimed at denying certain Americans the same rights and dignity as everyone else. But the tradition is too deeply rooted in our national character to ever truly die.

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