Mark Halperin in 2016. (Richard Shotwell/Invision/AP)

A purge is underway.

Emboldened by the defenestration of movie mogul Harvey Weinstein after sexual-harassment allegations that were first published in the New York Times, journalists in mainstream outlets have gotten busy. Emerson Collective, an outfit headed by Laurene Powell Jobs, bailed on a literary journal captained by Leon Wieseltier after it learned about his treatment of women while working at the New Republic, as first reported by Politico. CNN and The Post exposed allegations of sexual harassment by Mark Halperin during his time at ABC News. Then HuffPost completed a deeply reported story on the conduct of Hamilton Fish, publisher of the New Republic, after he was placed on leave during an investigation of his own past behavior. Others will likely fall.

Investigation is the only appropriate response to rot and corruption.

And so is unemployment. Of all the horrific behavior in which a journalist can partake, sexual harassment uniquely disqualifies its perpetrator from holding onto his journo pass. Take the example of Halperin, who acknowledged past inappropriate conduct with women, though he didn’t admit to all the details in public reports (in a statement, Halperin said he turned over a new leaf after departing from ABC News). After the story broke, Showtime, HBO, Penguin Press (publisher of the “Game Change” books that Halperin wrote with collaborator John Heilemann) and, lastly, NBC News/MSNBC cut their ties with him.

Wise decisions, all of them. Just think about the circumstances in which Penguin Press found itself with the planned “Game Change” book on the 2016 presidential race: Was Halperin really going to write about Hillary Clinton’s historical feat as the first woman to secure a major-party presidential nomination? Was Halperin really going to write about all the sexual-harassment allegations that piled up against candidate Donald Trump during the campaign? Was Halperin really going to write a tick-tock account of the “Access Hollywood” episode in which Trump said that his strategy with certain women was to grab them by the “p–––y”? Was Halperin really going to write about how Trump followed Clinton around on the stage in that October 2016 debate?

Those are only the most obvious thematic problems with having a confessed sexual harasser write a wide-ranging book on a wide-ranging presidential campaign. There’s a broader reason media companies can’t have such a man on the payroll. Sexual harassment is an abuse of power, not to mention a large-scale lie: Hire a woman, praise her hard work and credentials, then sexually assault/harass her.

No one who commits such criminal behavior/betrayal should be trusted to hold other powerful people to account.