Since Saturday, the president has repeatedly criticized "unscientific lockdowns" -- falsely portraying public health experts as supportive of harsh restrictions -- and argued against coronavirus-related limits on American society by repeating his months-old mantra, "The cure cannot be worse than the problem itself."
And since his own bout with the virus, Trump has made claims about his own supposed "immunity" standard campaign speech fare. "I'm immune and I can't give it to you," he boasted Wednesday" -- even though scientists do not fully understand how strong immunity may be or how long it might last.
"Remember, when you catch it, you get better, and you’re immune," he said in a Fox News interview last week, despite the lack of conclusive research and the the fact that hundreds of thousands have died after contracting it.
While he has largely avoided using the phrase "herd immunity" to describe the policies he has furthered, the president's views reflect those of a small subset of scientists with a powerful ally in the White House, Dr. Scott Atlas, a neuroradiologist with no background in infectious diseases who has supplanted Fauci and other top federal public health officials as one of Trump's top medical advisers.
The scientists argue that the United States should seek to achieve "herd immunity" to COVID-19 by allowing the natural spread of the virus through the population, while keeping only "vulnerable" groups -- like the elderly -- protected. Eventually, they say, enough people will get sick and recover -- and potentially become immune to reinfection, at least for some period of time -- that the rate of spread will diminish.
But a broad consensus of mainstream public health experts flatly rejects this idea, arguing it would lead to many millions of deaths and take an untold toll on an American populace rife with underlying medical conditions, like obesity, that make them more likely to suffer severe symptoms and die.
These top experts do, though, widely agree that extreme social-distancing measures can have adverse effects on society -- physically, mentally and financially -- and, when possible, should be avoided. They say that they, too, are against total "lockdowns," but that measures like mask-wearing and limiting the size of gatherings can lower the rate of infection.
"This idea that we have the power to protect the vulnerable is total nonsense, because history has shown that that's not the case," Fauci said Thursday in an interview with ABC News Chief Anchor George Stephanopoulos on "Good Morning America." "And if you talk to anybody who has any experience in epidemiology and infectious diseases, they will tell you that that is risky and you'll wind up with many more infections of vulnerable people, which will lead to hospitalizations and deaths.
"So I think that we just got to look that square in the eye and say it's nonsense," Fauci said.
The Trump administration has not treated it as nonsense, though.
In addition to pushing for an end to coronavirus-related restrictions and insisting the country fully "open up," Trump also has repeatedly emphasized -- often with misleading statistics -- that the virus only impacts the elderly or those with pre-existing conditions. His focus on those groups jibes with "herd immunity" adherents who minimize the risk to others.
In reality, thousands of younger Americans have died -- and millions have fallen ill.
The White House on Monday convened a conference call for reporters in part to draw attention to the Great Barrington Declaration, an online petition that argues in favor of achieving natural herd immunity while also using "focused protection" to safeguard the most vulnerable. The authors of the open letter boasted thousands of signatories, but Sky News found that among them were "homeopaths, therapists and fake names" like "Dr. Johnny Bananas" and "Dr. Person Fakename."
The Infectious Disease Society of America on Wednesday called the petition's ideas "inappropriate, irresponsible and ill-informed." In an open letter published Thursday in the leading medical journal The Lancet, an international group of top medical specialists endorsed a counter-petition called the John Snow Memorandum, which sharply opposes the natural pursuit of "herd immunity."
"Uncontrolled transmission in younger people risks significant morbidity and mortality across the whole population," the authors wrote in the memorandum, which has received backing from prominent epidemiologists. "In addition to the human cost, this would impact the workforce as a whole and overwhelm the ability of healthcare systems to provide acute and routine care."
No government epidemiologist or infectious disease expert was on the White House call, and when pressed, a senior administration official said the White House was not actually formally "endorsing" the petition.
"We’re not endorsing a plan," the official, who requested anonymity, told reporters. "The plan is endorsing what the president’s policy has been for months."
Fauci told ABC News on Thursday that the Great Barrington Declaration falsely portrayed prominent public health experts as supporting "lockdowns."
"That declaration has a couple things in it that I think are fooling people, because it says things that are like apple pie and motherhood," he said. "A, we don't want to shut down the country. I say that all the time. B, we do certainly want to protect the vulnerable."
In a statement provided by the White House, Atlas said "we emphatically deny that the White House, the president, the administration, or anyone advising the president has pursued or advocated for any strategy of achieving herd immunity by letting the coronavirus infection spread through the community." He said the Great Barrington Declaration authors "emphasized focused protection of the vulnerable and safely ending the shutdown of schools and society."
"Those specific policies are aligned with the president, who has repeatedly stated and pursued a strategy focused on saving lives by the following: aggressively protecting the vulnerable, preventing hospital overcrowding, and safely opening schools and society," Atlas said.
But John Brownstein, an epidemiologist at Boston Children's Hospital and professor of medicine at Harvard Medical School, said the Great Barrington Declaration did, in fact, back the idea of letting the virus rip through the community -- as long as the vulnerable were protected. "It's the same thing," Brownstein, an ABC News contributor, said. "I don't see the distinction."
Brownstein said the concept of "focused protection" was "theoretically exciting to think about" but was "not achievable in our population" because of the high level of underlying medical conditions in the population -- as well as the interconnectedness of society.
"We know that every single person is a bridge to a high-risk person," he said. "It's just not practical to think you could put people who are high risk separate from the population."
The president has for months pushed for the end of coronavirus restrictions -- including those recommended by the Centers for Disease Control and Prevention and other federal health officials -- flouting precautions like mask wearing and ignoring state and local regulations forbidding large gatherings.
A close ally, Florida GOP Gov. Ron DeSantis, has also embraced the researchers pushing the ideas behind natural "herd immunity."
In late September, DeSantis, a Republican, hosted a roundtable discussion with two of those who would later meet with Azar, Stanford University's Jay Bhattacharya and Harvard Medical School's Martin Kulldorff.
The next day, DeSantis, a Republican, lifted all coronavirus-related restrictions in the state.
This report was featured in the Friday, Oct. 16, 2020, episode of “Start Here,” ABC News’ daily news podcast.
"Start Here" offers a straightforward look at the day's top stories in 20 minutes. Listen for free every weekday on Apple Podcasts, Google Podcasts, Spotify, the ABC News app or wherever you get your podcasts.