Upon signing the Civil Rights Act of 1964, Bill Moyers related decades later, President Johnson said, “I think we just delivered the South to the Republican Party for a long time to come.”

It’s a popular story (though its truth is suspect), and it feels right for those who see race as America’s defining political narrative not only since 1964 but 1619. In fact, the Old South’s embrace of the GOP took a few decades. Richard Nixon’s Southern strategy and Ronald Reagan’s advocacy of states’ rights advanced it; Jimmy Carter and Bill Clinton, as sons of the South, mitigated it. Barack Obama cemented it.

The South became the cornerstone of the GOP’s congressional dominance in 1994, thanks to a coalition of economic and social conservatives. After the 2010 and 2014 elections, the tea partiers – roused after the election of the nation’s first black president – handed Republicans a record number of state legislatures. Like their congressional counterparts, they cut taxes for the wealthiest, rolled back economic regulation, and thwarted implementation of Obamacare. They also imposed citizenship and ID requirements to vote, reduced early-voting, drew gerrymandered districts, and with help from the Supreme Court undercut the effectiveness of the Voting Rights Act of 1965.

Debatable is the extent to which appeals to race have spawned the political realignment of the nation and especially the South. Indisputable is the loyalty of African Americans to the Democratic Party since Johnson used his overwhelming congressional majority to enact the Voting Rights Act, marking the beginning of the slow desertion from the party of working-class whites.

It’s conventional wisdom that presidential advisers from Pat Buchanan (architect of the South strategy) to Lee Atwater (creator of George H.W. Bush’s 1988 Willie Horton ad) to Karl Rove were expert at using race and class resentment to boost the GOP and its traditional agenda: advancing business interests.

At the start of the 2016 campaigns, the GOP coalition seemed to be intact, thanks to Obama. All the Republican candidates produced tax plans benefitting the same interests Reagan had championed. All pledged to repeal Obamacare (and none presented principles to replace it). Backed by action in the House, all promised to halt the trickle of Syrian refugees and to varying degrees discourage the immigration of Muslims and Latin Americans. Also backed by congressional Republicans, all favored “defunding” Planned Parenthood.

In the wake of Donald Trump’s victories in 10 of the first 15 primaries, the Republican establishment is freaking out, particularly over Trump’s alleged failure to disavow David Duke. The KKK apparently is over the edge, leading the House speaker and the Senate majority leader to condemn their party’s front-runner. It was the second time in a month Paul Ryan had criticized Trump, and Mitch McConnell was reported to have told colleagues he would drop Trump “like a hot rock” to protect Senate incumbents.

As McConnell recognized, the problem is not Trump as cause but as consequence: He’s taking dynamite to the party’s governing coalition. The establishment cares about taxes and regulation of commerce, and it draws social and religious conservatives with appeals to patriotism, Judeo-Christianity, and opposition to abortion (restrictions on which affect few Republicans who might want one).

Trump’s policy platform, to the extent he has one, is indistinct from his rivals and unimportant to his followers. His appeal stems from his anti-Obama “birtherism,” promise to wall off Latinos and Muslims, and pledge to “take the country back,” all with the most boorish rhetoric heard at least since Alabama’s George Wallace stood in the schoolhouse door.

Personally, I find the comparisons of Trump to Hitler, Mussolini and John Adams (who jailed opposition newspaper editors during his presidency) overblown. I have no idea whether Trump is more racist than the average American, but he appeals to those who are. He’s given his middle finger to the ways of the establishment, whose agenda has done little for the fortunes of wage-earners. The white working class – aware of its shrinking cultural significance and tossed to the margins of a low-wage, free-trade economy – is no longer buying what the planter class is selling.