One of the most spectacular fissures of this already dramatic political season has been the messy, public divorce of the Republican intelligentsia from the party's suddenly energized populist voter base. As Donald Trump grips crowds and racks up delegates with a blunt nationalist message of jobs, protectionism and "winning," true-believing conservatives—from dean of the conservative commentariat George Will, to Pete Wehner, who has worked for every GOP administration since Ronald Reagan, to Weekly Standard editor Bill Kristol—have peeled off in anti-Trump directions. When National Review, the flagship magazine of modern conservative thinking, devoted an entire issue to rejecting the GOP front-runner, it felt like a separation being finalized. Trump, of course, was unfazed, saying, "You have people that are in National Review—they're eggheads. They're just eggheads."

It's easy to lay the blame at Donald Trump's feet (after all, it's hard to imagine another Republican candidate of the last four decades rejecting National Review so cavalierly), but this year's split between intellectuals and the rank-and-file GOP goes beyond the front-runner. In fact, neither of Trump's remaining rivals, Ted Cruz nor John Kasich, is particularly cozy with the conservative intelligentsia. (Think tankers tended to coalesce behind Scott Walker, Jeb Bush and Marco Rubio, who are long since out of the race.) What's really going on is that the ideas that the conservative intellectual community has been peddling for decades have failed to appeal to an angry blue-collar voter base. What worked in Reagan's era just doesn't work anymore, and Trump is simply exploiting the divide.

If this divide deepens, it would mark the end of a romance between conservative intellectuals and the voters who propel their candidates into office that goes back several decades—one that has helped the GOP to win seven out of 10 the presidential elections, from Richard Nixon's first term to George W. Bush's 2nd. Conservative intellectuals helped build the GOP's basic modern platform—low taxes, small government, fewer regulations, toughness on crime, and traditional values—and, more deeply, helped the party craft its image as the "party of ideas," the one whose policy goals have largely defined the American conversation since Reagan's presidency.

Yet, as Trump's easy success reveals, the relationship is actual newer, and more uneasy, than most of the Right likes to think. As recently as the 1950s and 1960s, the "party of ideas" was unquestionably the Democrats—it was liberals, and liberal ideas, that defined the American policy conversation. Even the notion of a conservative intellectual was so unusual that Columbia Professor Lionel Trilling famously dismissed conservatism in 1950 as "irritable mental gestures which seem to resemble ideas."

It was only in the 1970s that the long-standing liberal dominance in the political world started to change. The conversion came about as a result of a series of savvy decisions by presidents, starting with Richard Nixon and accelerating under Ronald Reagan. The result has been deeply influential on American politics for two generations now. And if it were to end, and do so abruptly, such a split could well reconfigure American politics for decades to come.

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The relationship between liberal intellectuals and Democrats dates back to the early part of the 20th century. The progressive Democrat Woodrow Wilson, elected in 1912, was our only PhD president. The New Republic was founded in 1914 in part to bring progressive ideas into American politics. And in the 1930s and 1940s, Franklin Roosevelt brought a group of liberal Columbia University professors known as the "brains trust" into his administration. The so-called "liberal consensus" of the 1950s might have been a bit of a misnomer—there were even in those days some conservative flag bearers—but the term did correctly suggest that liberal anti-communism was the dominant intellectual force in American political life. John F. Kennedy made sure to exploit this prevailing liberal sentiment, recruiting prominent liberal academics such as Arthur Schlesinger and John Kenneth Galbraith into his administration.

Such a phenomenon would have been extremely unlikely on the GOP side of this aisle. When FDR enlisted the brains trusters, Republican Congressman Dewey Short denounced them as "theoretical, intellectual, professorial nincompoops who could not be elected dog-catcher." In the 1950s, while intellectuals swooned over Democratic presidential nominee Adlai Stevenson, Richard Nixon and other Republicans called him an "egghead." And when William F. Buckley created the conservative National Review in 1955, his mission statement clearly targeted the progressive intelligentsia dominating government at the time. It called for "standing athwart history, yelling Stop, at a time when no one is inclined to do so."

Given this history, perhaps it makes sense that it was an establishment Republican and an academically minded Democrat who first facilitated the marriage between GOP presidents and conservative intellectuals. In 1969, Richard Nixon hired Daniel Patrick Moynihan to work on domestic policy, but also to bring in new ideas and report on developments in the intellectual world at large. Moynihan was a heterodox Democrat who stayed in close touch with thinkers in the emerging world of conservative intellectuals, such as Irving Kristol—a neoconservative in the process of migrating from the left—and pro-growth Cold War strategist cum Hudson Institute founder Herman Kahn.

Moynihan warned the president that the GOP needed to develop a robust group of Republican intellectuals rather than rely on Democrats, ex-Democrats or even Democrats with some conservative inclinations, such as Moynihan, to fill the ranks of the conservative intelligentsia. In 1970, Moynihan wrote in a memo to Nixon that there was a limit to the outreach he could do on Nixon's behalf, emphasizing that this work "needs to be done by real Republicans." Nixon's successor, President Gerald Ford, followed Moynihan's advice, hiring St. John's College's Robert Goldwin—a student of the conservative University of Chicago political philosopher Leo Strauss—to tend to conservative intellectuals and to solicit ideas on such things as how to frame the White House approach to the upcoming bicentennial of America's founding.

Nixon and Ford started the process, but it was Ronald Reagan who fully integrated modern conservative thinking with real-world Republican politics. As a long-standing reader of National Review and other conservative magazines, Reagan was engaged in the world of conservative ideas and he was convinced that conservative intellectuals could not only frame the debate in books and in magazines, but could also serve as effective staffers carrying out policies. It was also a good time for him to be on the lookout for talent, as the growing number of conservative thinkers, many of whom were unwelcome or just uncomfortable at America's increasingly left-leaning universities, were quickly populating conservative think tanks.

Reagan discovered American Enterprise Institute scholar Jeane Kirkpatrick, his U.S. ambassador to the United Nations, by reading her legendary 1979 Commentary piece "Dictatorship and Double Standards." Kirkpatrick's neo-conservative foreign policy of openly recognizing friends, forging alliances based on a respect for self-determination and speaking out against enemies of freedom appealed to blue-collar Reagan Democratic voters. (Kirpatrick herself was a Democrat; she later became a Republican.) Another Commentary author and Democratic intellectual who became an important Reagan cabinet member was William J. Bennett, who migrated to the right because of his views on cultural issues.

These were just two of hundreds of conservative intellectuals Martin Anderson, a veteran of the Nixon White House, courted on behalf of the Reagan campaign in 1980, many of whom later served in the Reagan administration. Anderson had learned from his days with Nixon "that policy advisers from the intellectual world could be a tremendous asset to a campaign." And an asset they were, indeed: As Reagan critic Richard Reeves put it, conservative intellectuals "pulled together and honed a coherent set of ideas, a view of the world that was persuasively articulated by Reagan." Democratic operative and intellectual Bill Galston lamented in 1984 that "there were ideas in the Reagan campaign last time. That's how he won. On the strength of his ideas."

The worldview articulated by Reagan and his intellectuals was essentially this: Government was more of a problem than a solution; the Soviet Union was a danger that needed to be confronted; traditional values should be upheld; taxes and regulations should be reduced. The worldview adhered to the philosophy of "fusionism"—a creation of Frank Meyer, who argued in the National Review, that different strands of conservative thinking, from the traditionalist to the libertarian, could come together in the service of a single goal: defeating communism. The singular vision appealed both to conservative intellectuals and to blue collar workers that Reagan was courting for votes—and united them. It was a formidable coalition.

Throughout his presidency, Reagan continued to fortify his ties to the conservative intelligentsia. In 1981, the Heritage Foundation released a document called "Mandate for Leadership," a compilation of more than 2,000 specific policy proposals, 60 percent of which were adopted during Reagan's eight years. The Hoover Institution prepared a policy-priorities book, The United States in the 1980s, which Soviet Premier Mikhail Gorbachev decried to Reagan aides as "the real blueprint for Reagan administration policy." And in 1988, Reagan said that "today the most important American scholarship comes out of our think tanks, and no think tank has been more influential than the American Enterprise Institute." (In fact, Republicans were so successful at cultivating think tank support that the Democrats started copying the think tank model, creating the liberal Progressive Policy Institute and the Center for American Progress.)

After Reagan, the intellectual/candidate relationship became an essential part of the GOP campaign process. For presidential hopefuls, having intellectuals in their camp was understood to be a signal to primary voters of the candidates' conservative bona fides and their commitment to long-term, purposeful action. The intellectual primary became one of the crucial pre-voting contests for the GOP, along with the money primary for fundraising, and the staff primary for talent. Which is why, since the 1980s—and up until this year—GOP candidates have made the rounds at conservative think tanks and magazines in advance of a presidential run.

It was the intelligentsia that helped George W. Bush escape the lingering perception that he might be a disappointment to conservatives because of his more moderate father, George H.W. Bush. In 2000, the then-governor of Texas met with conservatives from the Hoover Institution to discuss key policy ideas for his presidential campaign. The group was impressed. Anderson, the ex-Reagan aide who helped set up the meeting, recalled thinking at one point in the meeting, "Hey, this guy's really good," and later helped gather conservative thinkers to flesh out policies for Bush.

As president, Bush kept up the outreach to the intellectual community. Bush White House aide Pete Wehner sent around semi-regular emails to his lengthy list of key conservative influencers. The emails, known as "Wehner-grams," provided updates of White House thinking. The relationship went in both directions, as conservative think tanks provided ideas and support to a number of Bush administration policies, including "the surge" in Iraq, crafted in part by the American Enterprise Institute—and the marriage served him well in his 2004 reelection.

Subsequent GOP candidates John McCain and Mitt Romney had bumpier relationships with conservative intellectuals at first—both received some criticism from for being insufficiently attentive to the right. But, these candidates did succeed in winning over the bulk of the conservative world once they were leading their nomination fights. There was never the slightest possibility of a #NeverMcCain or #NeverRomney movement.

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In 2016, the old model does not seem to be working. This cycle has revealed a chasm between the expectations of the GOP electorate and the conservative intellectual world. Much of this parting of the ways of course has to do with Trump, who does not appear to engage in outreach to conservative intellectuals and has few if any prominent conservative intellectuals on his team. In addition to dismissing National Review and not engaging with the think tanks, Trump has also made clear he wants to go it alone when it comes to idea generation, saying, "I'm speaking with myself, number one, because I have a very good brain."

To be fair, though, the emerging separation with GOP intellectuals is not solely a Trump-focused phenomenon. Neither Ted Cruz nor John Kasich are exactly darlings of the intelligentsia, either—or they weren't in the early stages of the campaign. Conservative intellectuals in this cycle were split by the largest crop of conservative candidates ever, but tended to coalesce at various times around Scott Walker, Jeb Bush and Marco Rubio, all of whom have exited the race. Having think tankers on their side did little to help those candidates connect with voters. Indeed, it could be argued that Jeb Bush's frequent references to books he was reading may have made it more difficult for him to appeal to voters on the ground.

Mainstream conservative think tank positions on free trade, U.S.-led internationalism, lower personal income tax rates, Social Security reform and immigration regularization simply do not appear to speak to today's high-anxiety voters. It is possible that the interests of Reagan-era intellectuals were more aligned with the GOP base than they are today. Lower taxes, small government, free-trade, and more immigration appealed to blue-collar voters in Reagan's day; they don't so much today. And so far, the elite has been reluctant to adapt.

So what does this mean for the future of the party—or, indeed, the future of both parties?

It's possible that we are seeing a temporary estrangement but not a complete divorce. Trump's success so far would have to be a blip—a temporary surge by a talented communicator whose lack of a core ideology leaves no lasting impression. For this to be the case, Trump would have to lose the nomination and whoever else get the nod—be it Cruz, Kasich or someone else—would have to have some kind of rapprochement with GOP intellectuals. In this case, we would see a return to the old paradigm with little change to the existing set of intellectual ideas.

But the rapprochement scenario is unlikely, especially since the GOP intellectuals are disconnected not only from Trump, but also from a significant portion of the GOP voter base. Some think tankers have spoken "reform conservatism"—a new mix of issues designed to appeal to today's struggling lower middle-class voters—but this effort itself is controversial among conservatives, and looks to be going nowhere. The reform camp has failed to achieve the fusionist consensus that Buckley and Meyer forged decades ago, which brought together the three main strands of conservative thought—economic, social and foreign policy—under one anti-communist umbrella.

Today's conservative intellectuals appear to be splintering, over Trump, over Cruz, over questions like immigration and America's proper role in the world. If they scatter, the loss of conservative intellectuals as a somewhat unified force could mean the end of the era of the GOP as the party of ideas. The battle of ideas is already an uphill battle for Republicans, especially given Democratic advantages in the faculty lounges and in the mainstream media—and without a reliable phalanx of intellectuals to help defend it in the larger marketplace of ideas, the Republican Party would eventually lose the respect of conservative-minded voters as well, potentially dooming it to suffer long-term electoral damage or outright disintegration. This could mean that the Democrats would take the initiative in shaping the country's policy directly for years or decades to come.

Another scenario, one that may be emerging already, is that GOP intellectuals split, and go in different directions. We have already seen some of the most adamant #NeverTrump folks suggest that they would vote for Hillary—it's possible that Democrats take advantage of this defection and recruit some of the top foreign policy intellectuals who signed a letter pledging never to back Trump into their party for the long-term. Such an effort could mirror the way Republicans drafted Democratic neocons like Kirkpatrick and Bennett in the 1970s and 1980s. Some "liberal-tarians"—libertarians who care about social issues more than economic ones and thereby sympathize with the Democrats—have already moved in the Democrats' direction. Under Trump, even more could follow. Other libertarians might stick with the smaller, purer libertarian party, recognizing that while it will not win elections, it represents a purer exprehssion of their beliefs. We might also see the development of an independent conservative party that is also more concerned with policy consistency than with electoral viability.

If there is a full-blown exodus of conservative intellectuals from the GOP, the policy experts who remain will risk being seen as more party-based than ideology-based. To remain relevant, they will have to reshape the GOP's issue mix toward more working-class issues, an effort that has proven elusive until now. And, it's also possible, if libertarians and conservatives defect to independent parties, the Republican party regulars could move towards the center in search of new voters, potentially drawing some moderate democrats who are disaffected by Bernie Sanders' pulling of the party to the left. Such a development could completely reshape both the Republican and the Democratic Party.

Whichever scenario happens, conservative intellectuals need to start considering where their political allegiances lie, and the GOP base needs to do the same. The alliance that served both sides so well for so long does not appear to be working—and the party's influence is at stake.