The national media’s shortcomings have been all too obvious in recent years as Donald Trump has gleefully thrown the norms of traditional journalism into a tizzy.

They’ve trafficked in false equivalence. Allowed President Trump to play assignment editor. Gotten mired in pointless punditry.

Granted, it’s been a mixed record. Journalists have done a lot right — they have pointed out lies, dug out what’s really happening, skillfully explained and analyzed.

But on Wednesday — as televised impeachment hearings begin in the House of Representatives — journalists need to be on their game. The stakes don’t get much higher when it comes to fulfilling their core mission: informing citizens of what they really need to know.

Here’s a refresher course in what needs to go right.

Stress substance, not speculation. Journalists and pundits love to ponder about how the public is reacting to news, though they aren’t much good at it.

Avoiding that would be a public service.

“Decline to speculate on how this is playing to voters in the swing states,” is the advice of New York University professor and press critic Jay Rosen.

A related issue: The extreme likelihood that the media will be focusing on the partisan fight, rather than the substance of what is being proved or not proved in the hearings themselves.

“Journalists can focus less on combat and more on clarity,” is how Rosen puts it.

Don’t let stunts hijack the coverage. If we know anything about Trump’s reaction when things get tough, it’s that he and his allies will haul out some attention-grabbing performance art and its distractions.

Trump will act out — because that’s what he does.

Recent example: Republican members of Congress barging into a secure facility on Capitol Hill where a Pentagon official was to testify before the House Intelligence Committee. It got plenty of TV and other media coverage and allowed Republican criticism of “the process” — however empty — to take center stage.

Not so recent example: Trump’s “news conference” at an October 2016 debate featuring three women who had accused Bill Clinton of sexual assault or sexual harassment in the past. It was an obvious effort to distract from the sexual-misconduct allegations against the then-candidate himself and to embarrass his general-election opponent, Hillary Clinton.

“The hearings are going to be a three-ring circus when they should be a one-ring circus,” said Tim O’Brien, executive editor of Bloomberg Opinion and a Trump biographer.

The media, he predicted, will find it hard “not to be distracted by the dancing clowns in one ring and the flaming-sword swallower in another, but to keep our eye on the tightrope walker in the center.”

They are going to have to make some choices about what’s really important and what is pure distraction.

Avoid Barr-Letter Syndrome. It was a little over six months ago that Attorney General William P. Barr took it upon himself to summarize the Mueller report in a misleading letter that the news media — pretty much en masse — represented as an accurate summation of the 448-page report about Russian interference in the 2016 election and its aftermath.

You might remember some headlines and news reports that said, essentially, “no collusion, no obstruction.”

Of course, that’s not what the report said, as Mueller himself later tried to set straight.

You’d think journalists would have learned that lesson. But then more recently came the release of a partial, rough summary of Trump’s phone call with Ukraine President Volodymyr Zelensky that asked for “a favor.” (The phone call, of course, is at the heart of the impeachment hearings, which explore Trump’s holding up military aid to Ukraine in trade for help in damaging his political opponents.)

In the initial round of coverage, almost all in the news media characterized this as “the transcript,” which strongly suggested that it was verbatim. It wasn’t — though it was damning enough, anyway.

Partly as a result, we see legions of Trump fans in T-shirts with the words “Read the Transcript.”(Actually, anybody who reads the transcript would discern abuse of power.)

“Effective propaganda,” as O’Brien characterized it. “It’s meant to delude.”

Propaganda brought to you in part by the insistent gullibility of the media.

Beware mealy-mouthed and misleading language. Punditry will be running even more amok than usual once the hearings begin. And we’ll be hearing a lot about what a divided nation we have and how ugly politics has become. We’ll be hearing the term “quid pro quo” endlessly.

Jon Allsop, writing in Columbia Journalism Review, suggested “quid pro quo” is inaccurate: “A president threatening to withhold military aid to a country unless it offers dirt on a domestic political rival, as Trump did, is not merely trading favors.” Questions about extortion or bribery — far riskier terms for would-be “balanced” journalists — are closer to the mark.

As for “polarization,” it’s a kind of false equivalence expressed in a single term, suggested Rosen: “We hear, ‘Oh things are so polarized now,’ when this is really about what’s happened to the Republican Party.”

In a potent Twitter thread last week, Ezra Klein of Vox pointed out that Trump’s abuses are so blatant that he “is the easiest possible test case for ‘Can our system hold a president accountable?’ And we are failing, because Republicans are failing.”

When journalists opt for safe language, when they pointlessly speculate, or succumb to Trump’s sideshow, they flunk the test.

Time to study up and ace it.

For more by Margaret Sullivan visit wapo.st/sullivan