Republican presidential candidate Donald Trump on Jan. 21. (Isaac Brekken/Associated Press)

JUST WHEN you thought the presidential campaign couldn’t get any more bizarre — just when you thought American politics might finally have exhausted the possibilities for cynicism and irresponsibility — certain Republican Party insiders have begun developing strange new respect for the candidate whose meteoric rise only yesterday made him the bane of “the establishment”: Donald Trump.

For all his quirks, the rationalization goes, the billionaire businessman is a man you can do business with. “Regardless of what your concern is with Trump,” Rep. Peter King (R-N.Y.) mused, in a typical expression of this new theory, “he’s pragmatic enough to get something done.” And so, if you can’t lick him, join him: At least he wouldn’t be inflexible ideologically and off-putting personally, like the only GOP candidate with an apparent chance to stop him — Sen. Ted Cruz (Tex.).

To be sure, we do not envy Republicans the Hobson’s choice they seem to face between Mr. Trump and Mr. Cruz. No doubt the latter could do lasting damage to the party brand, as the establishment fears. But Mr. Trump wouldn’t? “Concerns” about him do not stem from conventional political controversy — say, New Jersey Gov. Chris Christie’s handling of “Bridgegate.” Rather, the erstwhile casino magnate owes his rise in U.S. politics to a demagogic assault on ethnic and religious minorities, of the sort that, like previous such demagoguery in our history, has won him support — but also disqualifies him to lead a decent republic.

It was not very long ago that Mr. Trump was childishly mocking the physical disability of a New York Times reporter who had the temerity to contradict him (accurately) about Mr. Trump’s false claim that “thousands” of Muslims had celebrated the Sept. 11, 2001, terrorist attacks — a base insult of the reporter Mr. Trump compounded by falsely denying he had intended it. Yet former senator Bob Dole, the grand old man of the Grand Old Party, told the New York Times that Mr. Trump has “got the right personality” for the presidency.

Say what? Not only is Mr. Trump manifestly temperamentally unfit, but also he has not remotely fulfilled the first duty of an aspirant to the White House, which is to offer a plausible, specific set of policy proposals. Rather, he has issued platitudes — “make America great again” — and threats — “bomb the sh-- out of them” — that please crowds but offer no sense of what he might do with power, except, possibly, abuse it. In this very limited respect, Mr. Cruz, though every bit as noxiously divisive as Mr. Trump, is marginally preferable; at least he’s willing to offer specifics, such as opposition to ethanol subsidies.

Republican residential candidate Ted Cruz tells supporters he's not interested in bashing his Republican rival, Donald Trump, and that Americans don't care for politicians "behaving like petulant children." (Reuters)

Some in the GOP establishment now spin Mr. Trump’s policy emptiness as a feature, not a bug. When they describe him as someone who will “cut deals,” or turn to Washington’s elder statesmen for advice, they sound like people who imagine themselves filling the void in Mr. Trump’s head with the agendas of their own lobbying clients.

In other words, the insiders’ upbeat new take on Mr. Trump is a bet on his corruptibility — and a confession of their own.