Joe Lhota is brandishing his great coup over Bill de Blasio: that Gov. Cuomo told the Daily News that de Blasio’s promise to pay for universal pre-k by raising the state income tax on the very wealthiest is all but dead on arrival in Albany. Take that!

Perhaps Lhota, in his first run for office and down 40-plus points, doesn’t care about how a symbolic gesture works in politics. Or perhaps he simply doesn’t know.

Yes, Cuomo is happy to knife a fellow Democrat to position himself as a “moderate” for a White House run. The governor conjured up a theoretical exodus of 40,000 of the wealthiest New Yorkers hitting the highway for Florida should they be asked to pay even the very small amount de Blasio proposes, no doubt with Louis XIV chairs and Chippendale writing desks lashed Joads-style to the roofs of their Lamborghinis and Bentley SUVs.

Cuomo the Lesser will never actually be elected President, mostly because he has the personality of a bridge troll, but that’s beside the point. He’s done de Blasio a backhanded favor. A billionaire’s tax for tots was never going to do very much to solve the vast problem of wealth disparity in this city. It was only a way for the candidate to signal his sympathy with the many New Yorkers wondering how long they can afford to stay here.

Lhota agrees with the governor. We cannot levy even the tiniest tax on the very richest among us, the Republican explains, no matter how worthy the cause! Could any response have better made de Blasio’s point for him, about who New York is really run for — and how loathe they are to let any of their wealth trickle down?

But then, Lhota has run on clumsy symbolic gestures, rather than his considerable experience in government. His almost self-parodying attack ads warn that a weak-kneed, police-loathing liberal like de Blasio will “take us back” to the “bad old days.” He even castigated de Blasio for serving as a junior aide in the Dinkins administration, when “there were 2,000 murders a year” and our last race riot.

Well, we’re not going back, and it’s past time to dispel these hoary old right-wing myths. For starters, the millions of New Yorkers who now own co-ops and condos are not going to walk away from their classic sixes and go to New Jersey, the way so many renters did a generation ago.

Nor is it true that those renters were driven away in the first place by muddle-headed, criminal-coddling liberals. In fact, the number of police officers nearly doubled between 1955 and 1975 — when the fiscal crisis hit — going from 22,024 to 42,165, or nearly 8,000 more cops than there are right now. Far from being unduly restrained, the NYPD averaged more than 60 civilian killings a year in the early 1970s; in 2010, by contrast, there were eight.

The notion that the poor were being lavished with government largesse is equally delusional. In 1969, when the mean individual income in the city was $11,639, the average welfare family of four received all of $2,114 a year — a sub-poverty-level, survival stipend.

So what did go wrong? The short answer is that while poor, uneducated and low-skilled people flocked to New York as they always had, they no longer found the abundance of jobs the rapidly deindustrializing city had once offered. There were, however, ready supplies of guns and drugs.

Yes, poor leadership played a big role, too — but it was rarely provided by liberals.

From 1945 on, almost every leading liberal candidate for mayor got their clock cleaned in either the Democratic primary or the general election. Newbold Morris, Jonah Goldstein, Vito Marcantonio, Ferdinand Pecora, Rudy Halley, William Fitts Ryan, Paul O’Dwyer, Herman Badillo, Mario Cuomo, Bella Abzug, Percy Sutton, Frank Barbaro, Sal Albanese, Ruth Messinger, Mark Green — the pantheon of local liberal heroes — lost, often badly.

Generally, they fell to such old-school clubhouse hacks as William O’Dwyer, Vincent R. Impellitteri, Bobby Wagner II and Abe Beame, or, more recently, to a more conservative candidate like Ed Koch, Rudy Giuliani or Mike Bloomberg.

Even Lhota’s bogeyman, David Dinkins, was more of a traditional machine pol than anything else. Oh, and also the mayor who added 7,000 cops, made Ray Kelly police commissioner, and started the crime rate’s downward plunge.

You can argue voters rejected liberals — but you can’t then blame liberals for running everything into the ground.

So which is Bill de Blasio, Sandinista or Clintonista, radical or clubhouse regular?

It’s a good question, particularly considering how vague he has been about so many things as a mayoral candidate.

We’ll find out next year, but Lhota’s pursuit of the demagoguery of elections past is only obscuring the question.