A leopard’s spots are forever, as they say, so New Yorkers shouldn’t expect a radically different mayoralty when Bill de Blasio finally returns to City Hall.

Cats like to sleep late, after all, and so does Hizzoner.

As to what comes next, de Blasio offered a couple of hints Friday as he exited the national political stage (hard)-left.

“I’m going to redouble my efforts to improve the quality of life of everyday New Yorkers,” he declared, “proving that policies like guaranteed paid personal time off can work on a grand scale. I’m going to continue implementing universal health care and a Green New Deal in the nation’s largest city. And I promise I’ll fight for New Yorkers and workers everywhere to ensure there’s an actual plan to protect their livelihoods.”

That is, more foolish rhetoric from Sleepy-Eyed Bill.

He’s been talking like that since before he became mayor, but not delivering much of anything. This is not a bad thing, because redeeming his promises would depress the local economy profoundly — making it all that much more difficult for “ordinary New Yorkers” to make a decent living.

Besides, forging “new deals” of any sort is no business for mere mayors. They need to concentrate on the nuts and bolts of municipal governance — a devilishly difficult challenge under the best of circumstances.

Here, the administration’s refusal to face its responsibilities drives its most obvious failures. Yes, they were obvious before the mayor went away, but they’ve only gotten worse:

The city’s public housing stock continues its rapid deterioration. Residents can look forward to yet another winter without reliable heat, hot water or elevators — to say nothing of competent management.

Its public school system, always problematic, is drifting into a wholly avoidable racial crisis. The mayor’s decision to elevate “social justice” over basic classroom performance — and to hire a racially confrontational schools chancellor — is bearing predictable fruit.

City Hall’s willful abandonment of quality-of-life law enforcement is obvious everywhere. A simple subway ride all too often becomes a demoralizing vision of the future, and city streets are marred by vagrancy, petty harassment, personal sanitation issues and open drug use.

Want more? Challenges to the authority of the NYPD and poor police management are sure to lead to more serious crime, for example, and irresponsible municipal spending practices threaten the city’s future fiscal stability — and what about that billion-dollar mental health sinecure for his wife?

All these issues have one thing in common: However daunting, they are at least amenable to partial resolution by sober-minded, non-ideological, focused leadership.

The challenges the Giuliani and Bloomberg administrations met and managed weren’t so different than those vexing today’s city — but they were addressed by clear-eyed pragmatists who understood that filling potholes has very little to do with social justice.

Rudy Giuliani gets credit for defeating rampant street crime, but his success in imposing performance controls on infrastructure renewal projects was almost as significant. Mike Bloomberg demonstrated that focused management of land use and public education pays tangible dividends.

Nobody’s perfect, and neither were those two. But de Blasio, blinkered by ideology and hobbled by a near-nonexistent work ethic, hasn’t even tried. The results show it.

Add in de Blasio’s overly accommodating relations with political contributors. He has spent the bulk of his mayoralty under investigation for campaign law violations of one sort or another — and at week’s end, news broke that the feds are eyeing his presidential accounts.

So, more of the same? Perhaps.

But the details of past performance make this much clear: De Blasio’s next act is at least as likely to be dictated by surreptitious obligations to donors past and future as by public policy needs.

He would best serve his legacy by ditching the Park Slope Y; taking a page from Giuliani’s infrastructure book and applying it to the Housing Authority; sending his race-baiting schools chancellor packing; going back to broken-windows policing; getting right with the NYPD’s rank-and-file, and taking away his wife’s ThriveNYC hobbyhorse. For starters.

Most likely, though, he’ll just take another nap — leopards, spots and all that.

Bob McManus is a contributing editor of City Journal.