In Bill de Blasio’s New York, there is no shortage of bad ideas. But among the very worst is the so-called plan to desegregate public schools.

The proposal is so foul that it doesn’t even get credit for good intentions. It is the fruit of poisoned progressive politics and, as such, has almost nothing to do with helping nonwhite children do better in school.

If that really were the goal, the mayor could copy the methods of the best charter system. About 95 percent of the students in Eva Moskowitz’s Success Academy network are black and Hispanic, yet their schools often rank among the very best in the state.

In fact, if de Blasio wanted fast change, he could make Moskowitz chancellor and let her work her magic on the hundreds of thousands of kids trapped in perennial failure factories.

Fat chance. De Blasio hates Moskowitz and tries to strangle charters because he is in the pocket of the teachers unions. He would rather protect adult jobs — and get their votes and contributions — instead of doing what is best for children.

Which brings us to the plan his educrats cooked up to make it look as if he cares. Conveniently for his political ambitions, it reflects the social-justice fad of the moment that sees everything through the prism of race. Thus, it aims to cure a problem by starting with a flawed theory of its causes.

To be clear, it is an American tragedy that most black and Hispanic students lag most white and Asian students in reading, math and most other academic subjects. While there are individual exceptions, these patterns have vexed parents, educators and politicians for decades.

But to progressives like de Blasio, the cause of the problem is simple: white racism.

So they want a racial quota system where failing minority students are force-fed into classes of succeeding white and Asian students.

A test case on the Upper West Side’s District 3 shows the folly and the fury.

The proposal would reserve 10 percent of seats at middle schools for students whose average score on standardized tests was a 1. The state defines a score of 1 as “well below proficient,” but in reality, a 1 means the student showed up for the test and not much more.

An additional 15 percent of seats would be set aside for students whose average test score was 2, which the state defines as “partially proficient” in meeting standards.

They would presumably sit beside students who scored 3, which means “proficient,” or 4, which means “excel.”

One impact is obvious: Teachers would likely teach to the lowest common denominator, meaning top students would be bored to tears.

A second impact: The quota system would force some good students out of the best schools and into the worst ones. That would be their punishment for doing well.

Predictably, a relative handful of white parents who expressed concern about the plan are routinely being called racist by the media.

Even the new chancellor, Richard Carranza, got into the act by retweeting a video of parents at a meeting with school officials. Carranza later said he meant no offense and called on the city to “take a breath and let the process develop.”

Here’s a better idea: Carranza and his boss ought to go back to the drawing board. They should begin by focusing on helping failing students wherever they are instead of looking for social-engineering silver bullets.

Indeed, even if their current plan succeeded in lifting up the quota students, what about the 75 percent of students who would remain trapped in the failing schools? Is their fate unimportant?

And what happens to the succeeding students who get pushed out to inferior schools? Are they to be sacrificed for the greater political good?

There is also the question of how the quota students would be selected, and whether attendance and classroom conduct would be taken into account. Both are accurate predictors of academic success, and to pretend otherwise is educational malpractice.

Of course, real-world drawbacks don’t matter if your only aim is to score points with the radical left.

Besides, who cares about kids? They can’t vote.

Mueller’s loaded questions

The questions special counsel Robert Mueller reportedly wants to ask President Trump are reasonable — if you assume Mueller is at the beginning of a fishing expedition.

But when you consider that the FBI investigation into Russia, Russia, Russia was nearly a year old when Mueller picked it up a year ago, the questions seem preposterously vague and dated.

As Peggy Lee asked, “Is that all there is?”

The New York Times’ scoop on the questions set off a Washington game of who dun the leaking. The safe bet is someone in law enforcement, especially because Michael Schmidt is the lead byline on the story. He got many FBI leaks when James Comey was in charge, including Comey’s claim that Trump asked him for loyalty at a dinner.

Sourcing aside, the real issue is whether Mueller has anything that would justify Trump’s agreeing to a sit-down. To judge by the wide range of the 40 or so questions, Mueller is curious about everything and focused on nothing.

Comey’s firing, Michael Flynn, Paul Manafort, Attorney General Jeff Sessions, the 2013 Miss Universe pageant in Russia — they’re all on the list. Even media reports that Trump talked about firing Mueller are there.

Throw in questions about Trump’s business deals, and it’s easy to see why the president’s lawyers look at Mueller’s interview request as a giant perjury trap.

Because Trump has talked and tweeted about so many topics, almost any answer at variance could be the basis of charge, whether in court or Congress.

It’s possible the questions are a negotiating strategy, coming as Rudy Giuliani joins Trump’s legal team with hopes of brokering a quick settlement. In that case, the first move would be for Mueller to limit himself to issues where he has evidence Trump might have committed a crime.

If he doesn’t have any, the honorable thing would be to say so publicly and fold up shop. That would end the leaks and guessing games, and let Trump focus on his day job.

Yes, we do ‘mind’

The Post’s story on brain-wave-reading helmets that factory workers in China must wear showed a creepy side of technology. Jin Jia, a professor involved in the project, apparently had no sense of irony when she said of worker worries:

“They thought we could read their mind. This caused some discomfort and resistance in the beginning. After a while, they got used to the device.”

Yeah, people also got used to it in “Soylent Green.”

Sick joke’s on us

After Kathy Griffin’s faux beheading of Trump, CNN’s favorite unfunny comic apologized and took a break from public appearances.

She’s back — and more angry than ever. She’s even sorry she said she was sorry.

Sad.