What lies behind Donald Trump’s nomination victory? Received wisdom among conservatives is that he, the outsider, sensed, marshaled and came to represent a revolt of the Republican rank and file against the “establishment.”

This is the narrative: Republican political leaders made promises of all kinds and received in return, during President Obama’s years, major electoral victories that gave them the House, the Senate, 12 new governorships and 30 statehouses. Yet they didn’t deliver. Exit polls consistently showed that a majority of Republican primary voters (60 percent in some states) feel “betrayed” by their leaders.

Did these RINOs repeal Obamacare? No. Did they defund Planned Parenthood? No. Did they stop President Obama’s tax-and-spend hyperliberalism? No. Whether from incompetence or venality, they let Obama walk all over them.

But then comes the paradox. If insufficient resistance to Obama’s liberalism created this sense of betrayal, why in a field of 17 did Republican voters choose the least conservative candidate? A man who until yesterday was himself a liberal. Who donated money to those very same Democrats to whom the Republican establishment is said to have caved, including Chuck Schumer, Harry Reid and Hillary Clinton.

Trump has expressed sympathy for a single-payer system of socialized medicine, far to the left of Obamacare. He lists health care as one of the three main federal responsibilities (after national security); Republicans adamantly oppose federal intervention in health care. He also lists education, which Republicans believe should instead be left to the states.

As for Planned Parenthood, the very same conservatives who railed against the Republican establishment for failing to defund it now rally around a candidate who sings the praises of its good works (save for the provision of abortion).

More fundamentally, Trump has no affinity whatsoever for the central thrust of modern conservatism – a return to less and smaller government. If the establishment has insufficiently resisted Obama’s Big Government policies, the beneficiary should logically have been the most consistent and most radical anti-government conservative of the bunch, Ted Cruz.

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 means that Indiana 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. The Republican Party, 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 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 Trump-leaning neutrality. And Trump won.

True, Trump appealed to the economic anxiety of a squeezed middle class and the status anxiety of a formerly dominant white working class. But the prevailing conservative narrative – of anti-establishment fury – was different and is now exposed as a convenient fable. If Trump is a middle finger aimed at a Republican establishment that’s abandoned its principles, isn’t it curious that the party has chosen a man without any?

Trump lauds his own “flexibility,” his freedom from political or philosophical consistency. And he elevates unpredictability to a foreign policy doctrine.

The ideological realignment is stark. On major issues – such as the central question of retaining America’s global pre-eminence as leader of the free world, sustainer of Western alliances and protector of the post-World War II order – the Republican candidate stands decidedly to the left of the Democrat.

And who knows on what else. On entitlements? On health care? On taxes? We will soon find out. But as Trump himself says of being a conservative – at this point, who cares?

As of Tuesday night, certainly not the Republicans.

Charles Krauthammer is a columnist for The Washington Post. He can be contacted at:

letters@charleskrauthammer.com