Trump Proceeds With Post-Impeachment Purge Amid Pandemic

William B. Taylor Jr., the acting chief diplomat in Ukraine who also testified, was brought home early. John C. Rood, the under secretary of defense, was ousted. Joseph Maguire, the acting director of national intelligence, was pushed out early. Elaine McCusker, a Defense Department official who questioned the aid freeze had her nomination to be Pentagon comptroller withdrawn. Jessie K. Liu, who prosecuted Mr. Trump’s friend, Roger J. Stone Jr., had her nomination to be under secretary of the Treasury withdrawn.

Mick Mulvaney, the acting White House chief of staff, who admitted at a news briefing that the security aid to Ukraine was held up in part to leverage it to investigate Democrats (and then tried to take his statement back), was fired on March 6 even as the pandemic was beginning to spread more widely.

As the intelligence community’s inspector general, Mr. Atkinson received the whistle-blower complaint filed last August by a C.I.A. official raising questions about Mr. Trump’s dealings with Ukraine. Mr. Atkinson concluded that he was required by law to disclose the complaint to Congress, but the Trump administration initially refused until pressured by lawmakers.

His dismissal on Friday night, a time often used by a White House to bury news it prefers not to gain widespread attention, was disclosed in a letter to Congress but not announced by the White House press office. While it had been anticipated for some time, it still sent waves of concern among lawmakers and intelligence veterans.

“It’s awful. He did everything right,” Gen. Michael V. Hayden, a C.I.A. director under President George W. Bush, said of Mr. Atkinson. Mr. Trump, he added, was flouting the purpose of an inspector general. “He’s just doing it because he can do it.”

Democrats issued statements of protest on Saturday. “I am deeply concerned by President Trump’s purge of longstanding and respected career officials across our government,” said Senator Dianne Feinstein, Democrat of California. “Weakening our national security institutions is bad enough during a time of global calm; during the current instability we’re faced with, it’s particularly dangerous.”

Senator Charles E. Grassley, Republican of Iowa and a longtime champion of whistle-blowers, said Mr. Trump needed to provide more justification. “They help drain the swamp, so any removal demands an explanation,” Mr. Grassley said in a statement. “Congress has been crystal clear that written reasons must be given when I.G.s are removed for a lack of confidence. More details are needed from the administration.”