If Trump secures the Republican nomination, now an increasingly imaginable prospect, the party is likely to implode. Whatever rump organization survives will have forfeited any remaining claim to represent principled conservatism.
None of this will matter to Trump, however. He is no conservative and Trumpism requires no party. Even if some new institutional alternative to conventional liberalism eventually emerges, the two-party system that has long defined the landscape of American politics will be gone for good.
Should Trump or a Trump mini-me ultimately succeed in capturing the presidency, a possibility that can no longer be dismissed out of hand, the effects will be even more profound. In all but name, the United States will cease to be a constitutional republic. Once President Trump inevitably declares that he alone expresses the popular will, Americans will find that they have traded the rule of law for a version of caudillismo. Trump’s Washington could come to resemble Buenos Aires in the days of Juan Perón, with Melania a suitably glamorous stand-in for Evita, and plebiscites suitably glamorous stand-ins for elections.