It’s been a rough year for the Southern Poverty Law Center — deservedly so. And it just got more difficult, thanks to Attorney General Jeff Sessions.

The SPLC, formed in 1971 as an aggressive civil-rights nonprofit law firm, has become the left’s go-to arbiter of what constitutes a hate group. Its pronouncements are quoted without challenge by the news media, and it has an endowment of $300 million, enriched by major corporate donors.

Yet its overly broad definition of “hate” often goes far beyond truly vile outfits to include people and groups that simply don’t toe a politically correct line. That’s why the SPLC two months ago had to pay $3.4 million and publicly apologize to Maajid Nawaz, whom it had falsely labeled an “anti-Muslim extremist.” (He’s actually a practicing Muslim who opposes extremism.)

But that didn’t stop the Star-Ledger last week from devoting an editorial to denouncing New Jersey’s ICE spokesman, Emilio Dabul, for his “links” (as supplied by the SPLC) to “anti-Muslim fanatics.” This, even though the Star-Ledger admitted that Dabul’s own writings “showed no anti-Muslim bias.” It was all guilt by association — right from the SPLC playbook.

Now Sessions has ordered a review to ensure the Justice Department no longer partners with the SPLC and other groups that “unfairly defame Americans.”

Sessions acknowledged that the SPLC at one time “did important work in South”: As an Alabama prosecutor he worked with it to convict a Ku Klux Klan member who’d murdered a black teenager.

But nowadays, Sessions charged, it uses its hate-group designations “as a weapon” to “bully and intimidate” organizations of which it simply doesn’t approve.

Groups like the Alliance Defending Freedom, a Christian legal foundation that specializes in religious liberty — and quite effectively: It has prevailed in the US Supreme Court nine times in the last seven years. Yet the SPLC has defamed ADF as a “hate group,” a label Sessions rejected by appearing before the group.

As Ayaan Hirsi Ali, who’s also been smeared by the SPLC as an “anti-Muslim extremist,” has noted, the group these days is invested more in “profiting off the anxieties and white guilt of Northern liberals” than in actually upholding civil rights.

Sessions’ review is long overdue, and follows other government agencies that have backed away from the SPLC. It’s time for those who still merely parrot its smears to start taking a closer look.