Cruz’s entire career has consisted of promoting tea-party constitutionalism in revolt against party leaders who had joined “the Washington cartel.” Yet when Cruz got to his one-on-one with Trump at the Indiana OK Corral, Republicans chose Trump and his nonconservative, idiosyncratic populism.

Which makes Indiana a truly historic inflection point. It marks the most radical transformation of the political philosophy of a major political party in our lifetime. The Democrats continue their trajectory of ever-expansive liberalism from the New Deal through the Great Society through Obama and Clinton today. While the GOP, the nation’s conservative party, its ideology refined and crystallized by Ronald Reagan, has just gone populist.

It’s an ideological earthquake. How radical a reorientation? Said Trump last week: “Folks, I’m a conservative. But at this point, who cares?”

Who cares? Wasn’t caring about conservatism the very essence of the talk radio, tea party, grass-roots revolt against the so-called establishment? They cheered Cruz when he led the government shutdown in the name of conservative principles. Yet when the race came down to Cruz and Trump, these opinion-shaping conservatives who once doted on Cruz affected a studied Trump-leaning neutrality.