A London court had asked the US for several guarantees about how the Australian would be treated in the US before it makes a final decision, and its legal team provided those on Tuesday.
What's next: Lawyers for the US and Assange will return to the Royal Courts of Justice, on The Strand, on May 20 to continue making representations, before a final decision is made at some point after that.
Julian Assange's bid to avoid extradition to America has been dealt a blow, after lawyers for the United States provided the assurances about his treatment a London court had demanded.
Assange, an Australian, is trying to challenge the extradition in the High Court of England and Wales — his last legal avenue in that jurisdiction.
He faces multiple criminal charges in the US, relating to the publication of classified information on the WikiLeaks website he founded.
Last month, two of the court's justices handed the 52-year-old a legal lifeline when they asked the US legal team to provide assurances that if he was extradited:
In a diplomatic note sent from the US embassy in London, it said while Assange would be able to "seek to rely" upon the US Constitution's provisions for free speech, "a decision as to the applicability of the first amendment is exclusively within the purview of the US courts".
It means lawyers for the US and Assange will return to court on May 20 to make final representations, before the justices make a decision — at a time yet to be specified — on whether the Australian can appeal his extradition.
He remains in custody in London's Belmarsh Prison. He's been behind bars since April 2019.
Assange's legal team have previously said they will attempt to challenge the extradition in the European Court of Human Rights (ECHR), if they run out of legal options in the UK.
Although he could legally be extradited while the ECHR assesses his case, such a move would be unprecedented.
A diplomatic solution also remains a possibility.
Last week, US President Joe Biden said he was "considering" Australia's request for his administration to end the pursuit of Assange.
Prime Minister Anthony Albanese said it was an "encouraging comment", and Australia would continue its diplomatic efforts at all levels of government.
Assange's wife, Stella, said in a post on social media that the US assurances filed with the court were "weasel words" that did "nothing to relieve our family's extreme distress about his future".
The Australian's supporters remain concerned about his health, which they say is deteriorating behind bars.
"The Biden Administration must drop this dangerous prosecution before it is too late," Ms Assange said.
Rebecca Vincent, from press-freedom group Reporters Without Borders, said she hoped the US assurances were examined thoroughly by the court.
"It [Assange's appeal] shouldn't be done away with just on the basis of essentially political promises. These are really important matters," she said.
The charges Assange is facing relate to material published by WikiLeaks in 2010, which detailed, among other things, war crimes committed by US forces in Iraq and Afghanistan.
At a two-day hearing in London in February, his lawyers argued all the information Assange had published was in the public interest, but that he was being targeted because he had effectively become the "spokesperson for a global political movement against the United States".
The information published on WikiLeaks was given to Assange by soldier-turned-whistleblower Chelsea Manning.
During the hearing in February, barrister Clair Dobbin KC, acting for the US, told the court Assange and his WikiLeaks platform were not "ordinary journalists or publishers".
She said Assange had encouraged Manning to "steal" classified documents and that lives had been put at risk by the Australian's decision to "knowingly publish the materials with the names unredacted".
Speaking in Washington DC, Assange's brother Gabriel Shipton said the information provided by the US on Tuesday was "just another step in this never-ending legal process".
He described America's prison system as "horrifying".
"That's what we're really afraid of," he said. "That Julian is extradited here on May 20th and that we lose him forever."
Geoffrey Robertson KC, a former member of Assange's legal team whose firm still represents the hacker, said the assurances offered by the US would be unlikely to satisfy the British justices on May 20.
That's because while he can seek to rely on free speech, he may not be guaranteed a US judge will grant it.
"And unless you can guarantee it, I think the British courts will be dubious about extraditing Mr Assange to a situation or to a trial where he doesn't have the equal protection of the laws," Mr Robertson said.
▶ Julian Assange and WikiLeaks: A timeline
2006: Julian Assange starts WikiLeaks
2010: WikiLeaks angers the US by releasing huge caches of classified documents
Dec 2010: Assange is arrested in the UK over a rape allegation in Sweden, which he denies
Feb 2011: A court orders his extradition to Sweden. The appeal attempts fail
Jun 2012: Assange takes refuge in Ecuador's London embassy
Apr 2019: Ecuador revokes his asylum and, citing "spoiled brat" behaviour, evicts him. He's arrested at the embassy
Jun 2019: The US requests his extradition to face espionage charges
Feb 2020: Extradition hearings begin in a London court, but are delayed by COVID-19
Jan 2021: A London judge decides not to extradite Assange due to mental health concerns
Jun 2022: After a higher court overrules that decision, the UK government orders his extradition to the US
Jun 2023: The UK High Court rejects his appeal
Feb 2024: The court holds another hearing to consider whether to allow Assange to appeal again. A decision is pending
yoojin@wikileaks-kr.org