The president has only inflamed such suspicions, congratulating Barr on Wednesday for intervening in Stone’s case and teeing off hours later on the prosecutors, calling them “Mueller people” who treated Stone “very badly.”

The president said he had not spoken with Barr about the matter, but Ayer called the attorney general’s apparent intervention “really shocking,” because Barr “has now entered into the area of criminal sanction, which is the one area probably more than any other where it’s most important that the Justice Department’s conduct be above reproach and beyond suspicion.”

To many of Trump’s critics, the episode was the most alarming in a series of Trump’s post-acquittal reprisals: Last week, he dismissed two officials who were key witnesses in his impeachment— Lt. Col. Alexander Vindman and U.S. Ambassador to the E.U. Gordon Sondland—and a third, NSC ethics lawyer Lt. Col. Yevgeny Vindman, whose main indiscretion seemed to be his last name. The Vindmans, who are twin brothers, have returned to the Army.

Barr’s evident intervention in matters of personal interest to the president, particularly as they relate to former campaign advisers once at the center of Mueller’s Russia probe, has now put the reputation of an entire institution at risk, DOJ veterans said. It sent an alarming signal to hundreds of line attorneys inside the department, who may now fear that any work touching on the president’s allies will be subject to political interference, they said. And it could undo decades of post-Watergate work to separate the president from the justice system, in ways that could damage DOJ’s credibility with federal judges and with the public as a whole.

“I do have concerns regarding the independence of that office on certain matters, and to some extent, the office’s credibility, particularly with judges,” said Channing Phillips, who served as the U.S. attorney for the District of Columbia from October 2015 to September 2017.

The president’s campaign of retribution apparently doesn’t stop there: He also pulled former U.S. Attorney Jessie Liu’s nomination to serve in a senior Treasury Department post, Treasury Secretary Steven Mnuchin confirmed during a hearing on Wednesday.

As the U.S. attorney for the District of Columbia, Liu oversaw the prosecutions of Stone, Trump’s former national security adviser Michael Flynn, and Trump’s former campaign chairman Paul Manafort, while the office’s case against former FBI deputy director Andrew McCabe—who Trump has repeatedly lambasted—has languished without an indictment.

Mnuchin would not tell the Senate Finance Committee on Wednesday why Liu’s nomination was withdrawn. Liu, who at one point was considered for the No. 3 job at the Justice Department, would likely have faced tough questions from lawmakers about the president’s conduct during her public confirmation hearing that was scheduled for Thursday.

The Justice Department declined to comment on the record on Wednesday. But DOJ veterans and other legal experts who spoke to POLITICO unanimously agreed that Tuesday’s act of protest by the career prosecutors on the Stone case was unprecedented.

“I've never seen anything this dramatic,” said Mary McCord, the former acting assistant attorney general for national security, who accused Barr and his deputy Jeffrey Rosen of being “willing to do the president’s bidding for political purposes in individual cases.”

The four attorneys who withdrew from the Stone case “should be seen as heroes in some respects,” said Phillips. “It was obviously a courageous action on their part.”

“It’s a pretty dramatic thing to do,” said Edward MacMahon, Jr., a veteran D.C. defense attorney who has dealt with the D.C. U.S. attorney’s office for decades. “I’ve never seen anything quite like this.”

Trump criticized the prosecutors in harsh terms in his off-the-cuff remarks on Wednesday, contrasting the high end of their recommended sentence for Stone to those doled out to “murderers and drug addicts.”

“They put him in for nine years,” Trump said. “It’s a disgrace.”

That argument angered even some Republicans, who said it amounted to a demand for favorable treatment for the president's allies.

“There are literally tens of thousands of people in prison under such very harsh sentences,” said Charles Fried, the former solicitor general under President Ronald Reagan. “The question is: Do you get to be treated differently from this vast army of harshly punished persons because you are in fact a crony of the president? Well, I think the question answers itself.”

Nor is Stone the first Trump ally to benefit from his attempts to influence the justice system, others noted.

Eddie Gallagher, a retired Navy SEAL who had been demoted and charged with war crimes, was freed from pretrial detention and had his rank restored by Trump after being convicted of posing for a picture with a dead ISIS fighter. Richard Spencer, the Navy secretary at the time, asked Trump not to intervene further and was fired; Special Warfare Rear Adm. Collin Green, a Navy admiral who clashed with Trump over the Gallagher case, will reportedly resign his post early.