This post has been updated.

This was shaping up to be a potentially momentous weekend in the fight against the coronavirus for the Trump administration, with the Food and Drug Administration primed to approve the first vaccine within as little as a matter of hours.

But President Trump and the White House have decided to rather unhelpfully inject politics into the whole thing.

In an early-morning tweetstorm full of his usual score-settling, credit-seeking and conspiracy-theorizing, Trump suggested the FDA and its head, Stephen Hahn, weren’t moving fast enough.

“While my pushing the money drenched but heavily bureaucratic @US_FDA saved five years in the approval of NUMEROUS great new vaccines, it is still a big, old, slow turtle,” Trump said. “Get the dam vaccines out NOW, Dr. Hahn @SteveFDA. Stop playing games and start saving lives!!!”

Trump followed that up with a tweet saying, “I just want to stop the world from killing itself!”

The White House then went all in, with The Washington Post’s Josh Dawsey and Laurie McGinley reporting that White House chief of staff Mark Meadows on Friday told Hahn to submit his resignation if the FDA doesn’t clear the first vaccine by the end of the day.

These are extremely odd moves given how imminent the first approval appears; on Thursday night, the FDA’s board of independent advisers voted 17 to 4 that the benefits of the Pfizer-BioNTech coronavirus vaccine outweigh the risks for those age 16 and older — a key determination in that paves the way for approving the vaccine’s use on an emergency basis. (Some of the dissenters merely took issue with the ages specified.) The FDA assured Friday morning that it “will rapidly work toward” authorization of the vaccine.

So why do this now? The answer appears pretty simple: Because Trump can’t help himself. Even if it goes against the practice of the FDA — which is supposed to be insulated from political pressure — and has implications for public faith in its decisions, the important thing is apparently that Trump gets credit for pushing things along.

Trump has gone down this road before. When the FDA authorized hydroxychloroquine for emergency use this spring, Trump claimed credit for applying pressure on the decision on a drug that he and his allies had spent weeks hyping. Trump told Fox News at the time that “hydroxychloroquine is something that I have been pushing very hard. I got the very early approval from the FDA. It was going to take a long time, and Dr. Stephen Hahn, the head of the FDA, gave us an early approval, a very quick approval, a 24-hour approval.”

Except that’s not how the FDA’s approval process is supposed to work. Its decisions are supposed to be apolitical, so that people believe they were made solely based upon that and not by nonmedical professionals like a president.

And Hahn sought to combat that perception. Despite Trump saying he had pushed for the drug, Hahn assured STAT News, “I have not felt political pressure” or “exerted political pressure on FDA.” Colleagues defended him at the time.

About two months later, though, that pressure — again, by Trump’s own admission — was at-issue. The FDA reversed its emergency use authorization for hydroxychloroquine after deciding it wasn’t clear that the drug was effective in treating the virus or that its benefits outweighed the risks. The reversal led to the very obvious question of whether the drug would have been approved without Trump and his allies’ actions — a question which wouldn’t exist if Trump hadn’t focused so intently on the drug, despite the lack of evidence for its efficacy.

The prospect of political pressure on the FDA again cropped up again in August, when Trump again seized on an emergency treatment for a virus he so badly wanted to move past — this time: convalescent plasma. Trump welcomed Hahn to a news conference, at which Trump’s claims about the treatment’s prospects were characteristically over the top.

Except in this case, Hahn joined in the effort. Hahn echoed claims from Trump and Health and Human Services Secretary Alex Azar, saying the data suggest the treatment meant that, out of “100 people who are sick with covid-19, 35 would have been saved because of the admission of plasma.”

That’s decidedly not what the data actually showed, though. Hahn retracted the claim and acknowledged his error. How could an accomplished doctor like him get that wrong? We can only guess, but Trump has regularly lured officials around him into overhyping such claims.

And now the very significant public pressure for the FDA to do what Trump says is now in full view.

It’s perhaps understandable that some are questioning why the vaccines haven’t yet been approved — even as the first approval appears imminent. The particular Pfizer vaccine has already been approved by Britain, Canada, Bahrain and Saudi Arabia, but the FDA prides itself on a more rigorous process than those countries have.

The danger in Trump’s tweets, though, is readily apparent in recent polling. Many Americans — as many as 4 in 10 — say they don’t plan to take the vaccines.

For many of them, it seems to be a matter of questioning the need (doubts on that count are particularly prominent among Trump’s fellow Republicans). But there also remains significant doubt about the vaccines themselves.

A Pew Research Center poll released last week showed 24 percent of Americans don’t have confidence in the safety and effectiveness of the vaccines, and 62 percent said they would be uncomfortable being among the first to take them. In September, a poll from NBC News and SurveyMonkey showed 88 percent of Democrats and Democratic-leaning voters didn’t trust what Trump said about the vaccines. And a Washington Post-ABC News poll this summer showed 19 percent of Republicans said they wouldn’t take the vaccine and that it was because they didn’t trust vaccines in general. That number was 11 percent among Democrats and 12 percent among independents.

Getting Republicans to take the vaccines is generally the bigger hurdle, and they will likely be less concerned about the prospect of Trump having applied pressure on the process. But there are still other, very significant and Trump-skeptical swaths of the population with at least some degree of skepticism about the vaccine.

Trump on Friday yet again made clear he’s applying pressure to move the process along faster, which isn’t terribly helpful when it comes to allaying any lingering concerns. He has set himself up to take credit if and when the FDA begins approving the vaccines in the hours, days and weeks ahead — he did precisely that with hydroxychloroquine — which might be great for him. What’s great for public health, though, is another question entirely.

And his late intervention in this process — demanding that this happens now — is pretty much the opposite of what health officials want right now.