Liberal punditry is in a bit of a panic about tonight’s debate: You can tell by all the demands that moderator Lester Holt basically take Hillary Clinton’s side, and by the whining about how debates don’t really test the candidate’s qualifications for the presidency.

It’s wrong down the line.

Ever since Matt Lauer’s interviews of Trump and Clinton at a veterans’ event, the left’s been demanding that future moderators hit Trump hard — for example, showing “fairness” by correcting what they see as his lies.

Yet this has never been the job of the media folks asking the questions — their role is to get the candidates talking, and hold them to about equal time.

Trying to fact-check at the same time is perilous: Candy Crowley got it wrong late in a debate back in 2012, “correcting” a Mitt Romney statement that was perfectly true.

Worse (for the Clinton team, anyway), a moderator who keeps going after Trump is just going to strike most viewers as biased — and feed his anti-establishment aura.

Indeed, the ceaseless liberal-media attacks on Trump (extending even to silly hysteria over his son’s Skittles tweet) have been a huge factor in shoring up his support from the GOP base: In frantically pushing liberal buttons to drive voters to Clinton, they’ve also pushed conservative and even moderate buttons to push more voters the other way.

Plus, they’ve attacked Republican nominees this way for decades — so they’re inadvertently making Trump seem more like a normal Republican.

Bottom line: If Holt heeds liberal demands, he risks making himself look a fool or at least a partisan — and condemning himself to a future as an MSNBC host.

The more sophisticated excuse-making-in-advance, from the likes of Washington-media veteran Elizabeth Drew, is to insist the debates just shouldn’t “count,” because they test skills irrelevant to the presidency.

Which exactly misses the point: Viewers know that perfectly well. They watch anyway, because the show actually does give them a good chance to judge the candidates for themselves — to get a read on personality and values, not on the details of policy expertise.

Yes, there’s a certain “presidential” test, but it’s more about temperament than ability to field “gotcha” questions. And it’s a bigger issue this year, because Clinton’s opted to center her candidacy on the claim that Trump poses a unique threat to the Republic. (Yes, she’s tested countless positive messages, but not a one has stuck.)

Yet Trump himself actually claims to pose a unique threat — but to a corrupt establishment, in US politics and culture, that’s hostile to the concerns of many, maybe most, Americans.

An establishment that Clinton embodies. An establishment that’s in the tank for her, and against him.

Our guess is that the debate will turn on which threat most viewers think is the real one.