Matthew Continetti argues today that the potential nomination of Donald Trump would likely result in a wholesale realignment of the Republican Party. "The future of the GOP as we know it is in question," he writes, and Trump as nominee "would alter the character of the Republican Party in a fundamental way." In Continetti's view, Trump would replace the free-market, free-trade, pro-immigration conservatism of Ronald Reagan with a more nationalistic, isolationist, protectionist brand of politics that placed less emphasis on reforming or cutting domestic entitlement programs.
I think the article probably overstates the degree to which Trumpism is inconsistent with existing conservatism rather than an amplified form of its populist side, but I'm more interested in addressing the question of whether Trump's nomination would produce a wholesale, long-term change in the Republican Party. There are reasons to be doubtful.
Continetti makes his case by citing three historical parallels of presidential candidates who, he says, produced an ideological and coalitional change in their parties: Barry Goldwater in 1964, who led the takeover of the GOP by the modern conservative movement; George McGovern in 1972, who reflected the rising clout of racial minorities, feminists, Cold War doves, and cultural liberals within the Democratic Party; and Reagan in 1980, who benefited from the newfound political mobilization of the religious right and who established supply-side economics and moral traditionalism as essential components of the Republican creed.
But I'm struck by how different these examples are from Trump. Goldwater, McGovern, and Reagan were all the products of much broader movements that spent years pressing for influence within their home parties—laying intellectual groundwork, recruiting activists, gaining control of party institutions, persuading party-aligned voters. The presidential candidacies of these three men, while historically important, represented the flowering of a wider political mobilization that predated them and, crucially, had the capacity to survive the loss (in the first two cases) or departure from office (in the third case) of their presidential champion. (Democratic national leaders also moved away from McGovernism almost immediately, reverting to a strategy of attempting to contain the influence of liberal ideologues within the party.)
The Trump movement, in contrast, is all about Trump. His followers are devoted to him personally more than to any particular ideological tradition. They were not well-organized politically before his arrival, and they are unlikely to remain so after his defeat. There is no "Trump faction" among Republicans in Congress or in the party organizations that could take up the mantle if Trump himself is not elected, nor is there likely to be. Trump is certainly an important factor in this election, and is useful in revealing the political predispositions of a large portion of the Republican popular base, but he does not represent the mobilization of a political movement so much as the culmination of right-wing media influence over the Republican Party at the expense of its elected and organizational leadership.
If he were to be nominated, most of the GOP would make temporary peace with him, but he would be likely to lose (perhaps badly), giving the rest of the party leadership an easy way to write him off and return to their existing political objectives once the election is over. Perhaps a better historical comparison for Trump is Ross Perot, another rich businessman and political outsider who tapped into a significant popular sentiment and, for a time, appeared to some as a potentially revolutionary political figure, but whose "movement" was ultimately more about himself than the ideas on which he ran, and who showed no interest in doing the hard work and building the relationships with other actors necessary to sustain a lasting influence in politics.