In his 1996 campaign for the Republican presidential nomination, and in his 2000 campaign as the Reform Party nominee, Buchanan emphasized populist themes of economic nationalism and immigration restriction. But he was too much of a member of the Old Right that despised FDR and sought a return to the isolationism of Robert Taft and Charles Lindbergh to have much appeal to former New Deal Democrats. Buchanan's history of borderline anti-Semitic remarks led William F. Buckley Jr. to criticize him in "In Search of Anti-Semitism," (1992) and some of his associates like Samuel Francis were overt white racial nationalists.

For Reagan Democrats and their children and grandchildren, World War II showed America at its best. But Buchanan concluded a long career of eccentric World War II revisionism in 2009 with "Churchill, Hitler, and "The Unnecessary War": How Britain Lost its Empire and the West Lost the World," arguing that Hitler should have been appeased by Britain and the U.S.

Buchanan, in a recent interview, characterized Trump as his populist heir. "What Trump has today is conclusive evidence to prove that what some of us warned about in the 1990s has come to pass," he said. But the evidence is that Trump doesn't see it that way. Trump even competed briefly with Buchanan for the presidential nomination. The year was 2000, and Trump, encouraged by his friend Jesse Ventura, then governor of Minnesota, was considering a run for the presidential nomination of Perot's Reform Party, on the grounds that the Republican Party of George W. Bush and Karl Rove had "moved too far toward the extreme far right." Trump and Ventura hoped to rescue the Reform Party from the conservative allies of Buchanan, of whom Trump said: "He's a Hitler lover; I guess he's an anti-Semite. He doesn't like the blacks, he doesn't like the gays." Trump floated the idea of Oprah Winfrey as his running mate . In his 2000 manifesto The America We Deserve, Trump proposed a platform that included universal employer- based health insurance, gays in the military and a one-time 14.5 percent tax on the rich that would reduce the federal deficit and help eliminate the shortfall in Social Security.

In his press release announcing his withdrawal from the race for the presidential nomination of the Reform Party, Trump wrote: "Now I understand that David Duke has decided to join the Reform Party to support the candidacy of Pat Buchanan. So the Reform Party now includes a Klansman-Mr. Duke, a Neo-Nazi-Mr. Buchanan, and a Communist-Ms. [Lenora] Fulani. This is not company I wish to keep."

Compared to Trump, Buchanan was a flawed vehicle for the Jacksonian populism of the ex-Democratic white working class. So was another Pat, the Reverend Pat Robertson, television evangelist, founder of the Christian Coalition, and, like Buchanan, a failed candidate for the Republican presidential nomination. But while the mainstream conservative movement marginalized Buchanan, it embraced Robertson and other evangelical Protestant leaders like Jerry Falwell and James Dobson of Focus on the Family.

On social issues like abortion and gay rights, Buchanan shared the agenda of the religious right. But his advocacy of tariffs to protect American industry and immigration restriction threatened the mainstream right's consensus in favor of free trade and increased legal immigration. And his neo-isolationism threatened the post-Cold War American right's support of high military spending and an assertive global foreign policy.

Unlike Buchanan, Robertson and other religious right leaders did not deviate from the Republican Party line on trade, immigration, or tax cuts for the rich. Many of the rank-and-file members of the religious right shared the traditional populist suspicion of bankers and big business. But in the 1990s there was a tacit understanding that religious right activists would focus on issues of sex and reproduction and school prayer, leaving economics to free-marketers. In foreign policy, the Christian Zionism of many Protestant evangelicals made them reliable allies of neoconservatives with close ties to Israel and supportive of the Iraq War and other U.S. interventions in the Middle East.

From the 1980s until this decade, the religious right was the toothless, domesticated "designated populist" wing of the Republican coalition, and mainstream conservative politicians took it for granted that as long as they said they opposed abortion and gay marriage, evangelical voters would support free-market conservative economics and interventionist neoconservative foreign policy.

But even before the unexpected success of Trump in the Republican primary race beginning in 2015, there were signs that this generation-old bargain was coming undone. Hostility to both illegal immigration and high levels of legal immigration, a position which free-market conservatives had fought to marginalize, has moved very quickly from heresy to orthodoxy in the GOP. The opposition of populist conservatives killed comprehensive immigration reform under George W. Bush in 2007 and also killed the Gang of Eight immigration reform effort led in part by Senator Marco Rubio in 2013. The defeat of House Majority Leader Eric Cantor in the 2014 Republican primary for the 7th District of Virginia by an unknown conservative academic, David Brat, was attributed largely to Cantor's support for the immigration reform effort.

There were other signs of populist discontent with establishment conservative orthodoxy, for those who paid attention. No project is dearer to the hearts of mainstream movement conservatives than the goal of privatizing Social Security, a hated symbol of the dependency-inducing "statism" of the allegedly tyrannical Franklin D. Roosevelt. But George W. Bush's plan to partly privatize Social Security was so unpopular, even among Republican voters, that a Republican-controlled Congress did not even bother to vote on it in 2005. And a Republican-controlled Congress passed Medicare Part D in 2003-the biggest expansion of a universal middle-class entitlement between the creation of Medicare in 1965 and the passage of the Affordable Care Act in 2010. Blue collar Republican voters applauded, as libertarian think-tankers raged.

Conservative populists cannot be accused of inconsistency. Like New Deal Democrats before them, they tend to favor universal benefits for which the middle class is eligible like Social Security, Medicare and Medicare Part D, and to oppose welfare programs like Medicaid and the ACA which feature means tests that make the working class and middle class ineligible. The true inconsistency is on the part of the mainstream conservative movement, which has yoked together left-inspired crusades for global democratic revolution abroad with minimal-state libertarianism at home.

It remains to be seen whether Trump can win the Republican nomination, much less the White House. But whatever becomes of his candidacy, it seems likely that his campaign will prove to be just one of many episodes in the gradual replacement of Buckley-Goldwater-Reagan conservatism by something more like European national populist movements, such as the National Front in France and the United Kingdom Independence Party in Britain. Unlike Goldwater, who spearheaded an already-existing alliance consisting of National Review, Modern Age, and Young Americans for Freedom, Trump has followers but no supportive structure of policy experts and journalists. But it seems likely that some Republican experts and editors, seeking to appeal to his voters in the future, will promote a Trump-like national populist synthesis of middle-class social insurance plus immigration restriction and foreign policy realpolitik,through conventional policy papers and op-eds rather than blustering speeches and tweets.

That's looking ahead. Glancing backward, it is unclear that there has ever been any significant number of voters who share the worldview of the policy elites in conservative think tanks and journals. In hindsight, the various right-wing movements-the fusionist conservatism of Buckley, Goldwater and Reagan, neoconservatism, libertarianism, the religious right-appear to have been so many barnacles hitching free rides on the whale of the Jacksonian populist electorate. The whale is awakening beneath them, and now the barnacles don't know what to do.

Michael Lind is a Politico Magazine contributing editor and author of Made in Texas: George W. Bush and the Southern Takeover of American Politics.