In a stern lecture during a 2½-hour sentencing hearing, Jackson delivered an implicit rebuke to Trump, who has attacked her along with the jury and prosecutors in the high-profile case.

“There was nothing unfair, phoney or disgraceful about the investigation or the prosecution,” Jackson added, citing words that Trump has used.

The judge also said Stone “knew exactly what he was doing” when he posted an image on social media last year that positioned a gun’s crosshairs over her head.

“The defendant engaged in threatening and intimidating conduct toward the court,” Jackson said.

“This is intolerable to the administration of justice,” she added.

The initial sentencing memo by the original prosecutors in the case that called for seven to nine years in prison – later reversed by the Justice Department after Trump complained publicly – was thorough and well researched, the judge said, but added that such a sentence would be “unnecessary” for Stone.

Stone, who still has a sealed pending motion requesting a new trial, declined to speak at his sentencing hearing.

Stone’s lawyer, Seth Ginsberg, said Stone’s career as a self-described “dirty trickster” overshadowed other aspects of a spiritual man with no prior criminal record who has served as a mentor, loves animals and is devoted to his family.

“Mr Stone is, in fact, not simply that public persona, but a human being,” he said.

Jackson also said she would not discount tougher sentencing guidelines that apply to witness tampering and obstruction, which were among the seven criminal counts on which Stone was convicted in November.

The judge noted that Stone was not charged with or convicted of having any role in conspiring with Russia. But the judge said Stone’s effort to obstruct a congressional investigation into Russian election meddling “was deliberate, planned – not one isolated incident”.

Furious judge gags Trump adviser Stone who posted crosshairs photo of her

The investigators were not some “secret anti-Trump cabal”, the judge said, but members of Congress from both parties at the time when the committee was controlled by the president’s fellow Republicans.

Stone’s career as a Republican operative has stretched from the Watergate scandal era of the early 1970s to Trump’s campaign four years ago.

Wearing sunglasses and a dark fedora, Stone walked arm-in-arm with his wife and was surrounded by an entourage of family, friends and lawyers as he arrived at the courthouse. He strode past a giant inflatable rat dressed as Trump with a red tie and yellow hair – a common prop in street protests – and a sign calling for his pardon.

One onlooker shouted: “Traitor!”

Stone, known for his elegant attire, was clad in a dark grey pinstripe suit with a polka dot handkerchief in the pocket.

A jury of nine women and three men convicted Stone, 67, on November 15 on all seven counts of lying to Congress, obstruction of justice and witness tampering.

The charges stemmed from Special Counsel Robert Mueller’s investigation that detailed Russian meddling in the 2016 election to boost Trump’s candidacy. Stone was one of several Trump associates charged in Mueller’s inquiry.

The witness who Stone was convicted of tampering with was a radio personality named Randy Credico who had been summoned to testify before Congress and speak with the FBI about Russian election interference. In emails and texts, Stone told Credico among other things: “Prepare to die,” “You’re a rat. A stoolie,” and “Stonewall it.”

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Ginsberg, Stone’s lawyer, said his client did not deserve the tougher sentences for some of the charges against him specified by federal sentencing guidelines. But Jackson said the enhanced guidelines would apply.

“The defendant’s memorandum refers to this as ‘banter’ which it hardly is,” Jackson said.

As the hearing got under way, Trump complained on Twitter that the Justice Department should have prosecuted the former head of the FBI, James Comey, and his former deputy, Andrew McCabe, for what the president said was lying. The Justice Department investigated but opted not to prosecute both men.

“FAIRNESS?” Trump asked on Twitter.

Trump, who on Tuesday granted clemency to prominent convicted white-collar criminals including financier Michael Milken and former Illinois Governor Rod Blagojevich, has sidestepped questions about whether he will pardon Stone.

“We’re going to see what happens,” Trump said on Tuesday.

Prosecutors said Stone lied to the US House of Representatives Intelligence Committee about his attempts to contact WikiLeaks, the website that released damaging emails about Trump’s Democratic election rival Hillary Clinton that US intelligence officials have concluded were stolen by Russian hackers.

Trump, emboldened after his Senate acquittal in his impeachment trial, has attacked the prosecutors, jurors and judge in the case. After prosecutors last week recommended that the judge sentence Stone to seven to nine years in prison, Trump blasted them as “corrupt” and railed against this “miscarriage of justice”.

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US Attorney General William Barr then intervened and the Justice Department overruled the sentencing recommendation, prompting the four prosecutors to resign from the case. Congressional Democrats have accused Trump and Barr of politicising the US criminal justice system and threatening the rule of law.

Jackson pointed out that the Justice Department had not actually withdrawn the prosecutors’ initial recommendation, and had sharp words for John Crabb, the prosecutor newly installed on the case.

“I fear you know less about the case … than just about every other person in this courtroom apart from the defence attorney who just joined this team,” Jackson told him.

Crabb declined to say whether he wrote the court filing that reversed the original sentencing recommendation.

Stone, who has labelled himself an “agent provocateur” and famously has the face of former president Richard Nixon tattooed on his back, was arrested in January 2019 in a predawn FBI raid on his Florida home.