WASHINGTON (The Hill) — White House chief medical adviser Anthony Fauci on Sunday said if former President Donald Trump wins the presidency again in 2024, Fauci will not return to serve Trump in the White House. Dr. Fauci, the chief medical adviser to President Joe Biden, gave CNN’s Jim Acosta a plain “no” when asked if he would work with the 45th president again.

“If you look at the history of what the response was during the administration, I think, you know, at best, you can say it wasn’t optimal,” Fauci said. “History will speak for itself about that.”

Fauci, who also heads the National Institute of Allergy and Infectious Diseases, publicly crossed Trump over various health policies and misinformation during the initial months of the pandemic. Trump has strongly suggested his intent to run in 2024 but has not formally announced a presidential bid.

Early on, Fauci pressed for masks and social distancing, frequently warning of the perils of the pandemic, while Trump downplayed the severity of the novel coronavirus. As the pandemic wore on, Fauci earned the scorn of conservatives who wanted to end public health measures to curb the spread of COVID.

Fauci has remained a top pandemic adviser under the Biden administration, saying in January 2021 that it was “liberating” to work with the new president. “I can tell you I take no pleasure at all in being in a situation of contradicting the president, so it was really something that you didn’t feel you could actually say something and there wouldn’t be any repercussions about it,” he said then. “The idea that you can get up here and talk about what you know, what the evidence and science is, and know that’s it—let the science speak—it is somewhat of a liberating feeling.”