Race and ethnicity are hot topics for NYPD, but what about crime?

If you're following the turmoil at the NYPD, you probably noticed there's something missing from the conversation: any mention of crime.

You know, that whole thing about murder, rape and robbery, good guys and bad guys, victims and perps. Whether New Yorkers feel afraid to leave their homes and ride the subway and whether a jihadi next door is plotting mass murder.

Instead, reports about changes at the top are almost exclusively about race and ethnicity. And when it comes to race in the age of Bill de Blasio, all roads lead to Al Sharpton.

All race, all the time is Sharpton's game. And now, sadly, it's all that matters at the new NYPD. Make that the new, but not improved, NYPD.

Oh, don't worry about the changes, Police Commissioner Bill Bratton said Saturday. He promised to name new brass this week, adding, "I think the city and its many diverse communities will be very pleased."

In other words, as long as the top of the NYPD fits a quota system — or "looks like the city," in the words of activists — nothing else matters.

This is nuts.

Depending on who's talking, the man at the center of the storm, Chief of Department Philip Banks III, is very competent, a team player and a tough cop, or he's none of the above. All the public knows is that he was the highest ranking black official and suddenly resigned in a huff over a promotion that he regarded as being kicked upstairs.

Ditto for another official Bratton forced out, Rafael Piñeiro. A native of Cuba, he was the highest ranking Latino, and his last day was Friday.

For losing both men, Bratton stands accused of trying to make the NYPD a white male bastion. It's an unfair charge, but if his solution is to promote solely on the basis of race, he's surrendering his moral authority and integrity.

Let's be clear: Discrimination is illegal and repugnant. Affirmative action, meaning equal opportunity for all, is a virtue. Quotas are a scandal.

Yet New York has an ideological mayor who puts race and class warfare at the center of his agenda.

When promises of "social justice" devolve into a tawdry tally of how many blacks, whites, Latinos and Asians are at the table, individual merit is an afterthought.

Banks spent 28 years on the police force, and his career is now reduced to his skin color. Piñeiro, too, is now known for being Latino.

In any setting, that diminishes the enterprise and everybody involved. When it happens in the nation's best police force, it is a disaster.

This result was inevitable once de Blasio elevated Sharpton to co-police commissioner. It is telling that, as soon as he learned of Banks' resignation, the mayor did two things.

He chewed out Bratton for losing Banks. And he talked to Sharpton, where he no doubt promised swift action and begged for support.

As for Bratton, he's in a box of his own making. He got the job in part because he echoed de Blasio's slur that cops had driven crime to historic lows through racial profiling.

In fact, the department was rightly celebrated for saving thousands of lives, most of them black and Latino males who disproportionately commit crimes and are its victims.

For their valor and success, the NYPD and former Commissioner Ray Kelly were more popular among all New Yorkers than any mayor or public official in recent memory. They achieved that status by making the city safer for everybody, everywhere.

As they pick their new team, Bratton and de Blasio would do well to remember that lesson, one captured in an old saying that goes like this: "It doesn't matter whether the cat is black or white, only whether it catches the mice."