Everyone who already thought the case for President Trump’s impeachment was a slam-dunk went berserk Thursday, claiming that acting White House Chief of Staff Mick Mulvaney had just admitted to a quid pro quo with Ukraine.

Except that what Mulvaney “admitted” is that the administration was doing what it should — pushing a foreign government to cooperate in getting to the bottom of foreign interference in the 2016 campaign.

Virtually every media outlet in America — certainly all those that jumped on Mulvaney’s remarks — has spent most of the last three years painting such foreign interference as the blackest possible crime.

In fact, all Mulvaney did was repeat yet again that Trump “was worried about corruption with that nation” — and specifically say those worries extended to cooperation in “the look-back to what happened in 2016.”

Asked if Ukraine’s uncertainty about probing those matters was linked to the US holdup of military aid, he said “yes” — clarifying hours later that it wasn’t a quid pro quo.

Which it couldn’t be: Ukraine didn’t know about the holdup until weeks after President Volodymyr Zelensky’s call with Trump.

Critics complain that one specific issue Trump pushed is a “debunked conspiracy theory.” So what? The Obama administration and several Democratic senators at various times pushed Ukraine to cooperate in probes of possible Trump 2016 wrongdoing that eventually turned out not to exist.

Indeed, ongoing Justice Department investigations are trying to determine what if any lines the US intelligence community crossed improperly during those probes.

And Trump has been pushing Ukraine, quite appropriately, to cooperate with Justice.

Heck, Ukraine in 2017 started to mend fences over its admitted pro-Hillary Clinton meddling in the 2016 campaign.

In the press conference, Mulvaney also specifically ruled out any quid pro quo involving Trump’s offhand request to Zelensky to look into Hunter Biden’s activities there — which is supposedly the central charge in Democrats’ rush to impeachment.

Again, the fact that Zelensky didn’t know the aid had been frozen is a giant hole in the impeachment case and the “quid pro quo” charge. Indeed, when US diplomat Karl Volker made that point in testimony the other day, Rep. Adam Schiff complained, “Ambassador, you’re making this much more complicated than it has to be.”

Facts, as another president once noted, are stubborn things.