LONDON — Attorneys for Julian Assange argued Monday that the Trump administration is targeting the WikiLeaks founder for political reasons and that he would be denied a fair trial if extradited to the United States.

They also cautioned that their client's mental health is "fragile" and that he is at "high risk of suicide."

The Woolwich Crown Court proceeding marked a portentous new chapter in the long-running legal drama involving Assange.

His attorney Edward Fitzgerald told a packed courtroom next to Britain’s high-security Belmarsh prison that the prosecution by the U.S. Justice Department was “not motivated by genuine concerns for criminal justice but politics.”

U.S. prosecutors want the 48-year-old Australian to stand trial in federal court in Northern Virginia on charges that he violated the Espionage Act. Prosecutors allege that the anti-secrecy activist helped obtain and disseminate hundreds of thousands of pages of secret military documents and diplomatic cables regarding U.S. action in the wars in Iraq and Afghanistan. According to prosecutors, Assange helped Chelsea Manning, a former Army intelligence analyst, hack into government computers.

Fitzgerald argued that Assange would not receive a fair trial in the United States because of his foreign nationality and his political opinions.

The lawyer recalled that in 2017, then-CIA Director Mike Pompeo called WikiLeaks “a nonstate hostile intelligence service often abetted by state actors like Russia.”

Further, Fitzgerald said, Assange could face “inhuman and degrading treatment” in high-security isolation wings in U.S. prisons, as well as multiple life sentences.

Fitzgerald noted that the Obama administration in 2013 decided not to prosecute Assange, for fear that it would set a precedent that could ensnare journalists for publishing state secrets.

Fitzgerald asked what changed, saying, “The answer is: President Trump came to power.”

The U.S. case for extradition was presented by James Lewis, who told the court that Assange was not a journalist but a hacker who conspired to publish stolen classified documents. The material was not redacted, Lewis stressed, and contained the names of sources who had assisted U.S. forces in Iraq and Afghanistan, thereby putting their lives in danger. He did not provide any examples of actual harm being done to the sources.

Lewis said WikiLeaks’s initial publishing partners — the New York Times, the Guardian, El País, Der Spiegel and Le Monde — issued a joint statement saying they deplored the publishing of the sources’ names.

Lewis said the crimes that Assange is alleged to have committed would also be prosecutable, under similar circumstances, in the United Kingdom under the Official Secrets Act. But he added that it was not for the British court to decide whether Assange is a patron of a free press, a hacker, a whistleblower or a journalist, but to turn him over to the United States for trial.

If found guilty of the 18 charges in U.S. court, Assange could face up to a 175-year sentence. But Lewis argued that it was hyperbolic for the defense to claim that Assange would receive that entire sentence, describing to the court more likely sentences of 48 or 63 months.

Speaking before District Judge Vanessa Baraitser, Lewis said Assange “is not charged with disclosure of embarrassing or awkward information that the government would rather not have disclosed.” He is charged with conspiring to steal secret material.

Assange’s supporters fear he would be forced to serve any sentence in the supermax federal facility in Florence, Colo., in solitary confinement, beside al-Qaeda terrorists, Unabomber Theodore Kaczynski, and Robert ­Hanssen, a former FBI agent who spied for Soviet and Russian intelligence services against the United States.

Assange’s extradition proceedings are to be divided into two parts: this first week of legal arguments, followed by two or three weeks of witness testimony in May.

The court hearings are taking place beside the gray walls of Belmarsh prison, Assange’s home since police dragged him from the Ecuadoran Embassy, where he had been living, in central London in April.

In pretrial hearings, Assange’s attorneys signaled that they will argue their client acted as nothing more nefarious than a publisher and journalist — and that the prosecution is politically motivated, which should make extradition unlawful.

To bolster that assertion, Assange attorney Mark Summers has accused the CIA of spying on Assange, via a Spanish proxy, in the Ecuadoran Embassy. Further, Summers has asserted a link between the “reinvigoration of the investigation” against Assange and Trump’s presidency.

“This is part of an avowed war on whistleblowers to include investigative journalists and publishers,” Summers told the court last year. “The American state has been actively engaged in intruding on privileged discussions between Mr. Assange and his lawyer.”

Last week, Assange’s legal team again invoked Trump. A lawyer told the court that former congressman Dana Rohrabacher (R-Calif.), an ally of the president, offered to pardon Assange on Trump’s behalf if the WikiLeaks founder would say that Russia had nothing to do with the 2016 hack and leak of emails from the Democratic National Committee.

White House press secretary Stephanie Grisham called the suggestion of a pardon offer “a complete fabrication and a total lie.”

Experts in British extradition law say Assange’s attorneys face a tough task.

Nick Vamos, a former head of extradition at Britain’s Crown Prosecution Service, said British extradition courts are familiar with arguments about political motivation — just not in relation to requests from the United States.

“There is a very, very high degree of mutual trust and deference between two friendly nations,” Vamos said. “So it takes an awful lot to persuade a U.K. court” that the U.S. system isn’t fundamentally fair, “however much political intrigue is swirling around.”

This is in contrast to extradition cases to nations such as Russia, Vamos said, “where U.K. courts are actually quite ready to accept that somebody might not get a fair trial because [Vladimir] Putin or his cronies have got it in for them.”

Assange’s case has drawn comparisons to that of Harry Dunn, whose family says it is hypocritical that Washington is demanding Assange when it refused to turn over Anne Sacoolas, an American diplomat’s wife who is charged with causing the death of the British teenager. Sacoolas admitted she was driving on the wrong side of the road when she collided with Dunn as he was riding a motorcycle in August. She later fled Britain and claimed diplomatic immunity.