By Jonah Goldberg

Sell your Adam Smith ties, everybody, and smash your busts of Ronald Reagan. It’s all over.

Why? Because we have entered a new era of “nationalism,” or “patriotism,” or simply “Trumpism,” and the GOP will never be a traditionally and ideologically conservative party ever again.

That seems to be the conclusion of a vast and growing number of prominent conservative commentators who are sure that Donald Trump has changed, or destroyed, conservatism forever. Type “The Republican Party is Dead” or “GOP R.I.P.” into a search engine and you’ll get a sense of how far and wide this notion has spread.

Consider the inestimable Peggy Noonan, writing from the Olympian heights of the Wall Street Journal. She is increasingly adamant that Trump has ushered in a grand new era, a kind of Year Zero for the American right. The once-conservative masses no longer want to hear about liberty or freedom — they want to be “protected” by government, Noonan wrote in February.

As Trump solidified his power, Noonan set about to shoot the wounded. “Those conservative writers and thinkers who have for nine months warned the base that Mr. Trump is not a conservative should consider the idea that a large portion of the Republican base no longer sees itself as conservative,” she wrote last month.

A week later, Noonan again castigated anti-Trump forces in Washington. She insinuated that the Beltway elitists opposed to Trump seek to rebuild a post-Trump GOP as “a neoconservative, functionally open-borders, slash-the-entitlements party.”

That won’t happen, she insists, because “centers of gravity are shifting. The new Republican Party will not be rebuilt and re-formed in (the tony D.C. suburb) McLean, it will be rebuilt or re-formed in Massapequa (the Long Island suburb made famous by Joey Buttafuoco).”

Looking past the uncharacteristically weak and unfair snipes, this is somewhat amusing, given where Noonan works. The Wall Street Journal — arguably America’s best newspaper, by the way — is editorially closer to “open borders” than any other mainstream outlet. Its position on entitlements is even more stridently — and more correctly — in favor of major reform, as was Noonan not long ago. The term “slash” is beneath her, given that this is the sort of irresponsible left-wing rhetoric she once decried.

Which gets me closer to my real point. A few years ago, Noonan lionized another populist movement.

“Here is a great virtue of the tea party: They know what time it is. It’s getting late,” Noonan wrote. “If we don’t get the size and cost of government in line now, we won’t be able to. We’re teetering on the brink of some vast, dark new world — states and cities on the brink of bankruptcy, the federal government too. The issue isn’t ‘big spending’ anymore. It’s ruinous spending that they fear will end America as we know it, as they promised it to their children.”

The point here isn’t to criticize Noonan, of whom I am a fan (though I have profound disagreements with her of late). Again, she is hardly alone in claiming that Trump represents a welcome break from conservative ideas as we’ve known them — ideas I once associated Noonan with.

We can debate whether the New Thinking is good or bad. But we can all agree that one of the lessons of the Trump moment is that the conventional wisdom can change in an instant.

And yet to listen to Trump’s biggest media cheerleaders, most of them in that populist heartland of New York City, the new conventional wisdom will go on and on — forever. As George Orwell noted, such assumptions stem from power-worship; that the winner of the moment will be invincible for all time.

For instance, in 2010, when Noonan was praising the free-market and constitutionalist tea party, our entitlement situation was worse, our immigration problems were no better, and Big Government was roughly the same (serious) threat it is today.

Yet now she rallies to the protectionist and Constitution-agnostic Trump, despite Trump’s admission he will do nothing to fix entitlements or shrink government. The math on entitlements hasn’t changed, just the mood.

Hence Trump’s focus on a Muslim ban and a wall on the Mexican border. Whether or not those are good ideas (I think the former is insane, the latter sadly necessary), it seems rather silly to expect this agenda to permanently displace the ideas that have formed the backbone of the conservative movement for generations.

The mood will change again. It will be interesting to see whose ideas change with them.