More than 1,900 former Justice Department employees on Monday repeated a call for William P. Barr to step down as attorney general, asserting in an open letter he had “once again assaulted the rule of law” by moving to drop the case against President Trump’s former national security adviser Michael Flynn.

The letter, organized by the nonprofit Protect Democracy, was signed by Justice Department staffers serving in Republican and Democratic administrations dating back to President Dwight D. Eisenhower. The vast majority were former career staffers — rather than political appointees — who worked as federal prosecutors or supervisors at U.S. Attorney’s Offices across the country or the Justice Department in downtown Washington.

Protect Democracy, which counts Justice Department alumni among its members, has organized several similar letters critical of Barr’s decisions or other Trump administration actions. Most recently, in February, the group collected more than 2,600 signatures on a letter calling for Barr to resign after he intervened to reduce career prosecutors’ sentencing recommendation for Roger Stone, a longtime friend of Trump. Jonathan Kravis, one of the prosecutors involved in Stone’s case who resigned after Barr’s action, wrote in a Washington Post column published Monday that in both matters, “the department undercut the work of career employees to protect an ally of the president, an abdication of the commitment to equal justice under the law.”

The new letter asserted that its signers “continue to believe that it would be best for the integrity of the Justice Department and for our democracy for Attorney General Barr to step aside.” The group also called on Congress to formally censure Barr and asked a federal judge in Washington to hold a hearing to scrutinize whether to dismiss the case against Flynn.

“Our democracy depends on a Department of Justice that acts as an independent arbiter of equal justice, not as an arm of the president’s political apparatus,” the group wrote.

Among the signers were several high-profile Republican appointees, including Donald Ayer, a deputy attorney general under President George H.W. Bush; Charles Fried, solicitor general under President Ronald Reagan; and Stuart Gerson, who led the Justice Department’s civil division under Bush and served as acting attorney general briefly in the Clinton administration. Justin Vail, a policy advocate with Protect Democracy, said the group was “inundated with calls from former Department of Justice attorneys who wanted to speak out” after the action in the Flynn case.

A spokeswoman for Barr declined to comment.

Barr’s decision Thursday to reverse course and ask a federal judge to throw out Flynn’s case has roiled the Justice Department and renewed questions about whether the attorney general is bending federal law enforcement to the president’s will. Flynn had pleaded guilty in December 2017 to lying to the FBI about his interactions during the presidential transition with Sergey Kislyak, at the time the Russian ambassador to the United States. Trump ousted Flynn for, the president said, misleading the vice president about the matter.

But as he awaited sentencing, Flynn changed legal teams and sought to withdraw his plea and get the case thrown out, alleging Justice Department misconduct including entrapment by the FBI agents who interviewed him. Barr tapped Jeff Jensen, the U.S. attorney in St. Louis, to review how the case had been handled. Jensen said publicly last week that he recommended it be dropped.

In a filing Thursday, the Justice Department formally asked a judge to do so, arguing that the FBI did not have a valid investigative basis to interview Flynn, and thus whatever lies he told were not relevant to an investigation — which would be necessary to substantiate the criminal charge against him.

Soon before the filing, Brandon Van Grack, a career prosecutor on the case, moved to withdraw from it. Thursday’s filing was signed only by Timothy Shea, the D.C. U.S. attorney handpicked by Barr to lead that office. The Justice Department alumni expressed support for Van Grack’s decision and questioned the logic behind Shea’s reversal.

“The Department’s purported justification for doing so does not hold up to scrutiny, given the ample evidence that the investigation was well-founded and — more importantly — the fact that Flynn admitted under oath and in open court that he told material lies to the FBI in violation of longstanding federal law,” the group wrote.

Many on the political right have hailed Barr’s move, calling Flynn a victim of an overzealous FBI. Last week, Trump heaped praise on his attorney general for intervening. Barr, too, has publicly defended the move, telling CBS News it was an “easy” decision and one for which he was prepared to take criticism. As the group of Justice Department alumni acknowledged, their letter is unlikely to persuade him to step down.

“I also think it’s sad that nowadays these partisan feelings are so strong that people have lost any sense of justice,” Barr told CBS News. “And the groups that usually worry about civil liberties and making sure that there’s proper procedures followed and standards set seem to be ignoring it and willing to destroy people’s lives and see great injustices done.”

U.S. District Judge Emmet Sullivan must still approve the department’s request to drop the case and so far has not indicated what he will do. The Justice Department alumni asked Sullivan to hold a hearing with witnesses to examine Barr’s legal reasoning and “to deny the motion and proceed with sentencing if appropriate.”

“While it is rare for a court to deny the Department’s request to dismiss an indictment, if ever there were a case where the public interest counseled the court to take a long, hard look at the government’s explanation and the evidence, it is this one,” the group wrote. “Attorney General Barr’s repeated actions to use the Department as a tool to further President Trump’s personal and political interests have undermined any claim to the deference that courts usually apply to the Department’s decisions about whether or not to prosecute a case.”