There are many things we should remember about the events of late August and early September 2005, and the political fallout shouldn’t be near the top of the list. Still, the disaster in New Orleans did the Bush administration a great deal of damage — and conservatives have never stopped trying to take their revenge. Every time something has gone wrong on President Obama’s watch, critics have been quick to declare the event “Obama’s Katrina.” How many Katrinas has Mr. Obama had so far? By one count, 23.

Somehow, however, these putative Katrinas never end up having the political impact of the lethal debacle that unfolded a decade ago. Partly that’s because many of the alleged disasters weren’t disasters after all. For example, the teething problems of Healthcare.gov were embarrassing, but they were eventually resolved — without anyone dying in the process — and at this point Obamacare looks like a huge success.

Beyond that, Katrina was special in political terms because it revealed such a huge gap between image and reality. Ever since 9/11, former President George W. Bush had been posing as a strong, effective leader keeping America safe. He wasn’t. But as long as he was talking tough about terrorists, it was hard for the public to see what a lousy job he was doing. It took a domestic disaster, which made his administration’s cronyism and incompetence obvious to anyone with a TV set, to burst his bubble.

What we should have learned from Katrina, in other words, was that political poseurs with nothing much to offer besides bluster can nonetheless fool many people into believing that they’re strong leaders. And that’s a lesson we’re learning all over again as the 2016 presidential race unfolds.

You probably think I’m talking about Donald Trump, and I am. But he’s not the only one.

Consider, if you will, the case of Chris Christie. Not that long ago he was regarded as a strong contender for the presidency, in part because for a while his tough-guy act played so well with the people of New Jersey. But he has, in fact, been a terrible governor, who has presided over repeated credit downgrades, and who compromised New Jersey’s economic future by killing a much-needed rail tunnel project.

Now Mr. Christie looks pathetic — did you hear the one about his plan to track immigrants as if they were FedEx packages? But he hasn’t changed, he’s just come into focus.

Or consider Jeb Bush, once hailed on the right as “the best governor in America,” when in fact all he did was have the good luck to hold office during a huge housing bubble. Many people now seem baffled by Mr. Bush’s inability to come up with coherent policy proposals, or any good rationale for his campaign. What happened to Jeb the smart, effective leader? He never existed.

And there’s more. Remember when Scott Walker was the man to watch? Remember when Bobby Jindal was brilliant?

I know, now I’m supposed to be evenhanded, and point out equivalent figures on the Democratic side. But there really aren’t any; in modern America, cults of personality built around undeserving politicians seem to be a Republican thing.

True, some liberals were starry-eyed about Mr. Obama way back when, but the glitter faded fast, and what was left was a competent leader with some big achievements under his belt – most notably, an unprecedented drop in the number of Americans without health insurance. And Hillary Clinton is the subject of a sort of anti-cult of personality, whose most ordinary actions are portrayed as nefarious. (No, the email thing doesn’t rise to the level of a “scandal.”)

Which brings us back to Mr. Trump.

Both the Republican establishment and the punditocracy have been shocked by Mr. Trump’s continuing appeal to the party’s base. He’s a ludicrous figure, they complain. His policy proposals, such as they are, are unworkable, and anyway, don’t people realize the difference between actual leadership and being a star on reality TV?

But Mr. Trump isn’t alone in talking policy nonsense. Trying to deport all 11 million illegal immigrants would be a logistical and human rights nightmare, but might conceivably be possible; doubling America’s rate of economic growth, as Jeb Bush has promised he would, is a complete fantasy.

And while Mr. Trump doesn’t exude presidential dignity, he’s seeking the nomination of a party that once considered it a great idea to put George W. Bush in a flight suit and have him land on an aircraft carrier.

The point is that those predicting Mr. Trump’s imminent political demise are ignoring the lessons of recent history, which tell us that poseurs with a knack for public relations can con the public for a very long time. Someday The Donald will have his Katrina moment, when voters see him for who he really is. But don’t count on it happening any time soon.