Dr. Anthony Fauci had advised 5 Presidents before he met Donald Trump. But this President was different. When the country was hit by the Covid 19 pandemic, Trump often praised unproven treatments, talking about how injecting disinfectant could kill the virus. While trying not to contradict the President, Dr. Fauci, one of the top infectious disease experts in the U.S., became a calming presence in the pandemic, advocating practical remedies like social distancing. He also became the target of right-wing conspiracy theorists who sent him death threats. I talk to Dr. Anthony Fauci about his role in developing treatments for once-fatal diseases like AIDS, his staunch belief in science and how his life changed in the challenging years of the Trump administration.