After expressing frustration at the slow pace of approval for coronavirus treatments, and causing controversy by publicly linking the Food and Drug Administration to the “deep state” conspiracy theory, Donald Trump on Sunday announced the emergency authorization of convalescent plasma, a method which has been used to treat flu and measles, for Covid-19 patients.

Covid-19 has killed more than 175,000, cratered the economy and upended the president’s hopes of re-election. The White House has sunk vast resources into an expedited process to develop a vaccine, known as Operation Warp Speed, which aides hope will produce an “October surprise” before the presidential election on 3 November.

Making the announcement at a press conference, and with FDA commissioner Stephen Hahn standing with him, Trump added to days of White House officials suggesting politically motivated delays in approving a vaccine and therapeutics.

“This is what I’ve been looking to do for a long time,” Trump told reporters on Sunday at the White House. “I’m pleased to make a truly historic announcement in our battle against the China virus that will save countless lives.”

Critics say that name for the virus, based on where it originated, is racist. Furthermore, though more than 64,000 Covid-19 patients in the US have already been given convalescent plasma, a go-to tactic for new diseases, there is no solid evidence that it fights the virus.

On Saturday, Trump tweeted: “The deep state, or whoever, over at the FDA is making it very difficult for drug companies to get people in order to test the vaccines and therapeutics. Obviously, they are hoping to delay the answer until after 3 November. Must focus on speed, and saving lives!”

The “deep state” conspiracy theory holds that a permanent government of bureaucrats exists to thwart the president’s agenda. Former Trump campaign manager and White House adviser Steve Bannon, an enthusiastic propagator of the theory, has also said it is “for nut cases” and “none of this is true”.

House Speaker Nancy Pelosi called Trump’s tweet “scary” and “beyond the pale”.

The news site Axios, meanwhile, reported that trade adviser Peter Navarro was a driving force behind claims about the “deep state” and Covid treatments. Citing two sources in a meeting last Monday, Axios said Navarro aggressively confronted FDA officials, saying: “You are all deep state and you need to get on Trump Time.”

White House chief of staff Mark Meadows took the battle to the Sunday talk shows, telling ABC’s This Week: “We’ve looked at a number of people that are not being as diligent as they should be in terms of getting to the bottom of it. This president is about cutting red tape. He had to make sure that they felt the heat. If they don’t see the light, they need to feel the heat because the American people are suffering.”

Former FDA commissioner Scott Gottlieb defended his old employer.

“I firmly reject the idea they would slow-walk anything or accelerate anything based on any political consideration or any consideration other than what is best for the public health and a real sense of mission to patients,” he told CBS’s Face the Nation.

At the White House, in answer to a reporter from the fringe, far-right One America News, Trump doubled down.

“We broke the logjam over the last week,” he said, “to be honest I think that there are people in the FDA [who] can see things being held up and wouldn’t mind so much.”

Shortly after being challenged on his claims about plasma treatment compared to caution from officials including FDA commissioner Hahn, Trump ended the briefing.

There is little data on how effective plasma is or whether it must be administered fairly early in an illness, Dr William Schaffner, an infectious diseases expert at Vanderbilt University, told the Associated Press.

Hundreds of drugs are being developed, he added, and Trump “has made all kinds of therapeutic suggestions” that are not supported by science and are even dangerous.

Those statements from the president include claims about the possible value of treating patients with ultraviolet light and bleach. Trump reportedly recently became enthusiastic about oleandrin, a plant extract derived from a toxic shrub which scientists warned against.

The president is perhaps best known for his ardent embrace of the anti-malaria drugs hydroxychloroquine and chloroquine. In March the FDA granted emergency authorization for distribution of the drugs. In June the agency revoked it, in light of growing evidence they don’t work and could cause serious side effects. The FDA also warned doctors against prescribing the drugs in combination with remdesivir, a drug that was shown to help patients with Covid-19.

Axios cited a senior administration official as saying Navarro, “a fervent proponent of hydroxychloroquine … remained angry at the FDA for saying the drug didn’t work against Covid-19.”

Trump told reporters the order regarding plasma was “only possible … because of Operation Warp Speed. That is everybody working together. We’re years ahead of approval. If we went by the speed levels of past administrations we’d be two years, three years behind where we are today and that includes and vaccines that you’ll be hearing about very soon.”

The president also expressed support for the idea the American people have a “right to try” treatments still being researched.

Hahn has emphasized that routine evaluation procedures will remain in place to evaluate vaccine candidates. Furthermore, a top FDA official overseeing trials vowed to resign if the administration approved a vaccine before it was shown to be safe and effective.

Peter Marks, director of the Center for Biologics Evaluation and Research, made his promise during a call with pharmaceutical executives, government officials and others, Reuters reported.

“I think this administration has put more pressure on the Food and Drug Administration than I can remember,” Schaffner told the AP. “Everybody is just a little bit nervous.”