LONDON (AP) — The United States asked Britain’s High Court on Wednesday to overturn a judge’s decision that Julian Assange should not be sent to the United States to face espionage charges, promising that the WikiLeaks founder could serve any prison sentence he receives in his native Australia.

Chinese artist Ai Wei Wei joins supporters of Julian Assange as they stage a demonstration outside the High Court in London, Wednesday, Oct. 27, 2021. The U.S. government is scheduled to ask Britain’s High Court to overturn a judge’s decision that WikiLeaks founder Julian Assange should not be sent to the United States to face espionage charges. A lower court judge refused extradition in January on health grounds, saying Assange was likely to kill himself if held under harsh U.S. prison conditions. October 27, 2021

In January, a lower court judge refused an American request to extradite Assange on spying charges over WikiLeaks’ publication of secret military documents a decade ago. District Judge Vanessa Baraitser denied extradition on health grounds, saying Assange was likely to kill himself if held under harsh U.S. prison conditions.

An attorney for the U.S. government, James Lewis, argued Wednesday that the judge was wrong to conclude that Assange’s mental health was too fragile to withstand the U.S. judicial system. Assange “has no history of serious and enduring mental illness” and does not meet the threshold of being so ill that he cannot resist harming himself, the lawyer said.

Lewis said American authorities had promised that Assange would not be held before trial in a top-security “Supermax” prison or subjected to strict isolation conditions, and if convicted would be allowed to serve his sentence in Australia.

Lewis said the assurances “are binding on the United States.” “Once there is an assurance of appropriate medical care, once it is clear he will be repatriated to Australia to serve any sentence, then we can safely say the district judge would not have decided the relevant question in the way that she did,” he said.

Assange’s lawyer, Edward Fitzgerald, said in a written submission that Australia had not agreed to take Assange if he is convicted. Even if Australia did agree, Fitzgerald said the U.S. legal process could take a decade, “during which Mr. Assange will remain detained in extreme isolation in a U.S. prison.”

He accused U.S. lawyers of seeking to “minimize the severity of Mr Assange’s mental disorder and suicide risk.” Assange, who is being held at London’s high-security Belmarsh Prison, had been expected to attend the two-day hearing by video link, but Fitzgerald said Assange had been put on a high dose of medication and “doesn’t feel able to attend the proceedings.”

Assange later appeared on the video link at times during the day, seated at a table in a prison room, wearing a black face mask. Several dozen pro-Assange protesters held a boisterous rally outside London’s neo-Gothic Royal Courts of Justice throughout the day, calling the prosecution politically motivated and demanding it be dropped.

The demonstrators included Chinese dissident artist Ai Weiwei, who said Assange’s case “relates to our society, it relates to our freedom of expression, it relates to our individual human rights, and we have to watch the government”

The two justices hearing the appeal — one is England’s most senior judge, Lord Chief Justice Ian Burnett — are not expected to give their ruling for several weeks. That will likely not end the epic legal saga, however, since the losing side could seek to appeal to the U.K. Supreme Court.

U.S. prosecutors have indicted Assange on 17 espionage charges and one charge of computer misuse over WikiLeaks’ publication of thousands of leaked military and diplomatic documents. The charges carry a maximum sentence of 175 years in prison, though Lewis said “the longest sentence ever imposed for this offense is 63 months.”

American prosecutors say Assange unlawfully helped U.S. Army intelligence analyst Chelsea Manning steal classified diplomatic cables and military files that WikiLeaks later published. Lawyers for Assange argue that he was acting as a journalist and is entitled to First Amendment freedom of speech protections for publishing documents that exposed U.S. military wrongdoing in Iraq and Afghanistan.

In her January judgment, Baraitser rejected defense arguments that Assange faces a politically motivated American prosecution that would override free-speech protections, and she said the U.S. judicial system would give him a fair trial.

WikiLeaks supporters say testimony from witnesses during the extradition hearing that Assange was spied on while in the embassy by a Spanish security firm at the behest of the CIA — and that there was even talk of abducting or killing him — undermines U.S. claims he will be treated fairly.

Assange, 50, has been in prison since he was arrested in April 2019 for skipping bail during a separate legal battle. Before that he spent seven years holed up inside Ecuador’s London embassy, where he fled in 2012 to avoid extradition to Sweden to face allegations of rape and sexual assault.

Sweden dropped the sex crimes investigations in November 2019 because so much time had elapsed. The judge who blocked extradition in January ordered that he must stay in custody during any U.S. appeal, ruling that the Australian citizen “has an incentive to abscond” if he is freed.

Outside court, Assange’s partner Stella Moris said she was “very concerned for Julian’s health,” and called it “completely unthinkable that the U.K. courts could agree” to extradition. “I hope the courts will end this nightmare, that Julian is able to come home soon and that wise heads prevail,” she said.

Associated Press writer David Keyton contributed.