Putting an entirely new spin on the concept of “public campaign finance,” Mayor Bill de Blasio is ruthlessly exploiting his official powers to get First Lady Chirlane McCray elected as Brooklyn borough president in 2021— with a pretty obvious eye on moving the family back into Gracie Mansion eight years later.

Most despicably, the failed ThriveNYC project (which has already cost taxpayers around $1 billion) is a central part of the scam.

McCray’s ThriveNYC mental-health and wellness podcast just launched — in partnership with a Brooklyn-based cultural nonprofit that took in $1.2 million in city funding in 2019.

For the first show, she brought in recent Yale grad Dante de Blasio (no longer employed by Bill de Blasio’s presidential campaign) to serve as guest co-host.

It’s “All in the Family,” de Blasio style. Or maybe the Corleones?

As veteran local pol Sal Albanese tweeted, “This is an obscene use of taxpayer $ for blatant political purpose.”

It’s also shameless, since Thrive was plainly intended to showcase McCray’s leadership — but wound up showcasing her inability to manage anything.

By all accounts, the mayor is looking to cash in political chits left and right to install McCray as Brooklyn beep. Hey, someone has to support the family after term limits force him off the public payroll on Jan. 1, 2022.

This cynical abuse is of a piece with the $358,000 security bill footed by taxpayers during Bill’s ridiculous presidential bid — which includes the $490 tab for seven cops to tag along as the mayor watched his beloved Boston Red Sox play the Angels while he was in Los Angeles taping a political podcast shortly before he folded his prez campaign.

And most of the $1.3 million he raised for that farce came from big donors plainly hoping for favors from city government.

City taxpayers also covered the NYPD’s costs for de Blasio’s Nevada trip to endorse Bernie Sanders last weekend, as they will for the mayor’s future electioneering — all of which is aimed at maybe lining up a future federal job for him, in case Brooklynites choose a different beep.

Plainly, it’s never crossed his mind to find some private-sector hustle.