Although things between him and Trump have been frosty for months now the last time they spoke was in early June their cold war went into overdrive last weekend, when the Washington Post reported that Trump's aides are circulating talking points criticizing Fauci for his handling of the virus.
But the coronavirus outbreak is a different beast than the myriad controversies Trump has weathered throughout his presidency, complicating the president's efforts to message his way through the crisis.
Events like the Russia investigation and impeachment were politically seismic, but their threat was contained largely to Trump and those around him. That's not the case with a pandemic that, as of Tuesday, has infected more than 3.3 million Americans and killed over 135,000 people across the country, according to data from Johns Hopkins University .
A string of media reports over the last several months have painted a damning picture of how Trump hampered the US's recovery by ignoring more than a dozen warnings about the pandemic from intelligence officials, cutting funding to public health agencies, demonizing medical experts, and spreading misinformation about the severity of the outbreak.
Further complicating matters for Trump is the American public's substantial approval of Fauci and distrust of the president when it comes to the pandemic. Indeed, the Post reported on Monday that Trump is rattled by Fauci's soaring reputation compared to his own, particularly in the months leading up to November's election.
In all three surveys, respondents gave Fauci and New York Gov. Andrew Cuomo the highest ratings for their handling of COVID-19 and ranked Trump and senior White House adviser Jared Kushner at the bottom.
In a national poll of 1,337 registered voters conducted by The New York Times and Siena College in mid-June, 76% of respondents said they trusted Fauci for "accurate information" about the COVID-19 pandemic compared with just 26% who said they trusted Trump.
The White House's talking points, which some have described as opposition research, attacked Fauci for not taking the outbreak seriously enough early on. They also skewered Fauci for putting out inaccurate information about asymptomatic transmission and shifting stances on the implementation of lockdown measures to contain the spread of the outbreak.
White House press secretary Kayleigh McEnany denied this week that the talking points are opposition research and insisted that Trump and Fauci have "a good working relationship."
But she and other Trump aides, like White House trade adviser Peter Navarro, have largely echoed those points and criticized Fauci for giving the public what they characterized as conflicting advice.
However, as the Post and multiple public-health experts pointed out, the White House's talking points left out critical portions of Fauci's comments in which he specified that he was making assessments based on the best available information at the time, and that the outlook could dramatically shift down the road.
"Taking quotes from Dr. Fauci out of context to discredit his scientific knowledge and judgment will do tremendous harm to our nation's efforts to get the virus under control, restore our economy, and return us to a more normal way of life," the Association of American Medical Colleges said in a statement on Monday.
The AMA added that it was "extremely concerned and alarmed" by the attacks against Fauci.
Others pointed out that Fauci isn't the problem.
Jeremy Konyndyk, who oversaw the Obama administration's response to the Ebola outbreak in West Africa, said the president is the biggest threat against a strong recovery based on his lukewarm response to the coronavirus and ignorance of repeated warnings from medical experts.
"So look, @WhiteHouse, I think it's great that you care about retroactive accountability for officials' prior mistakes on Coronavirus. And all I'm saying is, Fauci's maybe not the main guy you should be worried about on that score," Konyndyk tweeted on Monday.
Even Republican Sen. Lindsey Graham, who is one of Trump's biggest allies on Capitol Hill, rallied to Fauci's defense on Tuesday.
"We don't have a Dr. Fauci problem," Graham, who is the chairman of the Senate Judiciary Committee, told reporters. "We need to be focusing on doing things that get us to where we need to go. So, I have all the respect in the world for Dr. Fauci. I think any effort to undermine him is not going to be productive, frankly."
Oma Seddiq and Grace Panetta contributed reporting.