Speaking to reporters at the White House, Trump mused about House Intelligence Committee Chairman Adam Schiff (D-Calif.) being the whistleblower’s “informer,” without citing evidence. Schiff was the public face of the House’s effort to impeach the president.

“They give this whistleblower a status that he doesn’t deserve. He’s a fake whistleblower,” Trump concluded. “And frankly, somebody ought to sue his ass off.”

Trump’s remarks underscore his deep, long-running disdain toward the officials and lawmakers whose actions led to his impeachment in the House over his alleged efforts to pressure Ukraine’s president to investigate his political rivals.

Despite Trump’s vehement defense of his decision to terminate Atkinson, some Republican senators expressed uneasiness with the president’s actions and praised Atkinson.

Sen. Chuck Grassley, for example, said the firing of Atkinson “demands an explanation.”

The Iowa Republican, who crafted the nation’s whistleblower protection statutes, did not criticize Trump for firing Atkinson, as several top Democrats did when Trump relieved Atkinson of his duties late Friday night. But he said the Trump administration should explain the move in greater detail.

“[Inspectors general] help drain the swamp, so any removal demands an explanation,” Grassley said in a statement on Saturday. “Congress has been crystal clear that written reasons must be given when IGs are removed for a lack of confidence. More details are needed from the administration.”

Also on Saturday, the office of the director of national intelligence announced that Thomas Monheim, who has served in top legal positions throughout the intelligence community, was named acting inspector general.

In a letter to the House and Senate intelligence committees late Friday, Trump informed lawmakers that he was terminating Atkinson because he no longer had confidence in him.

Atkinson drew strong criticism from Trump’s allies after he provided Congress with the whistleblower complaint that detailed Trump’s interactions with Ukrainian President Volodymyr Zelensky, among other actions by White House and State Department officials.

POLITICO reported on Saturday that Atkinson sent a letter to Senate Minority Leader Chuck Schumer (D-N.Y.) last month in which he said the past six months were “a searing time for whistleblowers,” and he criticized those who have failed to defend whistleblowers — without mentioning the president.

“Those repeated assurances of support for whistleblowers in ordinary matters are rendered meaningless if whistleblowers actually come forward in good faith with information concerning an extraordinary matter and are allowed to be vilified, threatened, publicly ridiculed, or — perhaps even worse — utterly abandoned by fair weather whistleblower champions,” Atkinson wrote in the letter to Schumer.

Senate Intelligence Committee Chairman Richard Burr (R-N.C.) praised Atkinson on Saturday for his “professionalism and responsiveness,” but did not mention the circumstances of Atkinson’s firing.

“Like any political appointee, the Inspector General serves at the behest of the Executive,” Burr said. “However, in order to be effective, the IG must be allowed to conduct his or her work independent of internal or external pressure.”

Sen. Susan Collins (R-Maine), a moderate who often criticizes Trump’s conduct, said Atkinson’s removal was “not warranted” and that Trump’s explanation was not “persuasive.”

“While I recognize that the president has the authority to appoint and remove Inspectors General, I believe Inspector General Atkinson served the Intelligence Community and the American people well, and his removal was not warranted,” Collins said in a statement.

Top Democrats strongly condemned the move, dubbing it an abuse of power and an act of politically motivated retaliation. Michael Horowitz, who chairs the Council of the Inspectors General on Integrity and Efficiency, lauded Atkinson for his “integrity, professionalism, and commitment to the rule of law.”

“That includes his actions in handling the Ukraine whistleblower complaint, which the then Acting Director of National Intelligence stated in congressional testimony was done ‘by the book’ and consistent with the law,” Horowitz added.

A congressional source said that while the House and Senate intelligence committees were given the 30-day notice of Atkinson’s removal as required by law, he was immediately placed on administrative leave, meaning that his tenure effectively ended Friday night.

Burgess Everett contributed to this report.

