First he went after the prosecutors who recommended a multiyear sentence for his friend Roger Stone. Then President Trump turned his Twitter ire to the “witch hunt disgrace” of special counsel Robert S. Mueller III’s investigation, which led to Stone’s indictment. But perhaps most surprising was Trump’s decision to target U.S. District Judge Amy Berman Jackson — who will determine Stone’s fate when he appears in her courtroom next Thursday.

It was not the first time Trump had gone after a federal judge or questioned the judiciary, but Tuesday’s attack was nevertheless vexing to current and former judges as Jackson prepares to decide whether to send the president’s friend to prison — and for how long.

“The timing is outrageous, and the notion that you’re attempting to influence a judge,” retired federal judge Nancy Gertner said.

“He’s trying to delegitimize anyone appointed by someone other than him and say that the only people who can be trusted are Trump judges,” she said.

The targeting of Jackson, who has presided over a set of cases involving Trump associates in the past year, is the latest in a drumbeat of disparagement from the president when he disagrees with rulings. After Trump criticized a district court judge who ruled against the administration in 2018, Chief Justice John G. Roberts Jr. took the rare step of responding and countering the president’s characterization of the judge as an “Obama judge.” Roberts, nominated by President George W. Bush, has himself been the target of the president’s ire. Trump labeled him an “absolute disaster” for his vote in 2012 to uphold the Affordable Care Act.

Other presidents have expressed dismay at court decisions, as President Barack Obama did during his 2010 State of the Union address after the Supreme Court’s decision in Citizens United v. FEC opened the door for corporations and unions to spend freely in elections. But Trump’s criticism comes as Stone’s sentencing is pending and the president is being lobbied to pardon his friend. Michael Caputo, a former campaign adviser to Trump, on Wednesday announced a committee to raise money for Stone’s appeal alongside a petition drive for him to be pardoned.

“Roger Stone stood up for Donald Trump. Now America should stand up for Roger Stone. Please take just a few seconds to help by signing the petition to pardon Roger Stone!” says the committee’s website.

When asked Wednesday by reporters whether he was considering a pardon for Stone, Trump said, “I don’t want to say that yet.”

The White House did not respond to requests for comment.

Stone’s sentencing by Jackson is scheduled for Feb. 20. A jury convicted Stone in November on charges of witness tampering and lying to Congress about his efforts to gather damaging information about Trump’s 2016 presidential election opponent Hillary Clinton. Stone’s defense has asked for a sentence of probation, citing his age, 67, and lack of criminal history.

On Tuesday, Trump criticized as unduly harsh the initial sentencing recommendation of seven to nine years made by front-line prosecutors. Shortly thereafter, the Justice Department signaled that it would seek a more lenient sentence for Stone, a move that prompted all four career prosecutors to withdraw from the case — and one to resign from the government.

Hours later, Trump targeted Jackson for her treatment of another ally of his, Paul Manafort, his former campaign chairman, and suggested that the judge had been soft on Clinton.

“Is this the Judge that put Paul Manafort in SOLITARY CONFINEMENT, something that not even mobster Al Capone had to endure? How did she treat Crooked Hillary Clinton? Just asking!” the president wrote, sharing a tweet that named Jackson as the judge who sentenced Manafort.

Just one day before Trump voiced his displeasure with Jackson, the judge issued a ruling favorable to the administration. She threw out a lawsuit filed by historians and watchdog groups seeking to compel the White House to preserve records of the president’s calls and meetings with foreign leaders.

Jackson, 65, has played a central role in cases involving Trump associates and Mueller’s Russia investigation. She sentenced Trump’s former deputy campaign chairman, Rick Gates, in December. She presided over the trial of Gregory B. Craig, a Democratic former White House counsel who was charged in a spinoff from the Mueller probe and was acquitted in September.

Before adding 3½ years to the almost four years Manafort received after his trial in Alexandria, Jackson said: “This defendant is not public enemy number one, but he’s also not a victim either. There’s no question this defendant knew better, and he knew exactly what he was doing.”

She did not as a judge, however, have any authority over the conditions of Manafort’s confinement, as the president suggested in his tweet.

Jackson, a 2011 nominee of Obama’s, was born in Baltimore, the daughter of a U.S. Army-trained physician. A graduate of Harvard University and its law school, Jackson spent time both as a federal prosecutor in Washington and as a white-collar defense lawyer. With lawyer Robert P. Trout, she represented former Louisiana congressman William J. Jefferson on corruption charges after a search turned up $90,000 in cash stashed in the Democrat’s freezer.

Jackson, through a court spokeswoman, declined to comment.

Her current and former colleagues say she is unquestionably independent and will not be pressured by Trump’s tactics, even if she would prefer not to be the subject of his attacks.

“I have no doubt that she will not be deterred, pressured or intimidated by the unwarranted and inappropriate remarks of the president or anyone else for that matter,” said a colleague, who spoke on the condition of anonymity because of the sensitivity of the matter.

U.S. District Judge Paul Friedman, another colleague of Jackson’s on the court in Washington, recently warned of the consequences of similar attacks from the president. Trump, Friedman said in a speech, “seems to view the courts and the justice system as obstacles to be attacked and undermined, not as a coequal branch to be respected even when he disagrees with its decisions.”

Jackson has already tangled with Stone. Last February, a photo of the judge on Stone’s Instagram account seemed to violate a gag order she had imposed on him because of concerns about pretrial publicity. The image appeared to show a gun sight’s crosshairs next to a photo of Jackson’s face. Stone said he wasn’t sure who posted the image, but he said he viewed it as a Celtic cross. He apologized for it.

Paul G. Cassell, a former federal judge in Utah, called the personal nature of the president’s attacks “highly unusual and an extraordinary departure from the way things are ordinarily handled.”

But, he said, the nation’s system of government insulates judges from political pressure because they are appointed for life. While most judges would prefer not to be the target of attacks on social media, including from the president, he said, the independence of the judiciary provides protection from repercussions.

“Judge Jackson will simply move forward and decide the case,” said Cassell, now a law professor at the University of Utah, “and ignore the surrounding atmospherics from the president and the others who are responding to him.”

Spencer S. Hsu and Allyson Chiu contributed to this report