LONDON — Britain’s Supreme Court on Monday said it had refused the latest appeal by Julian Assange, the embattled WikiLeaks founder, to prevent his extradition to the United States.
The announcement was a blow to Mr. Assange, coming just months after a high court said he would be able to appeal a decision by a lower court that would allow for his extradition. However, he has still not exhausted all of his legal options in the British courts, his lawyers said.
The Supreme Court in a statement Monday said that it had refused permission to appeal “because the application does not raise an arguable point of law.”
Mr. Assange’s legal team indicated that the decision on extradition would now be referred back to the lower court that originally assessed the U.S. request, which would then put the final decision in front of Priti Patel, the U.K.’s Home Secretary.
Ms. Patel would then decide whether to order or refuse the extradition, but Mr. Assange’s defense team will also be entitled to make submissions to her before she issues a decision. Ms. Patel’s office did not immediately respond to a request for comment.
A U.S. Justice Department spokesman also declined to comment.
Crucially, the Birnberg Peirce law firm, which is representing Mr. Assange in the case, said he had not exhausted his ability to appeal in regard to “other important issues he raised previously” in that lower court decision.
The firm said it regretted “that the opportunity has not been taken to consider the troubling circumstances in which requesting states can provide caveated guarantees after the conclusion of a full evidential hearing.”
The firm’s statement referred to the initial argument for appeal, which had turned on the timing of when the United States made assurances that Mr. Assange would be treated humanely in an American prison if he’s found guilty.
“In Mr. Assange’s case, the court had found that there was a real risk of prohibited treatment in the event of his onwards extradition,” the firm said.
Mr. Assange was charged in the United States under the Espionage Act in connection with obtaining and publishing secret government documents centered around U.S. actions during the wars in Afghanistan and Iraq. They were published on WikiLeaks in 2010 after being leaked by Chelsea Manning, a former military intelligence analyst.
If Mr. Assange were extradited to the United States and faced a trial, the case could raise profound First Amendment issues. His prosecution has alarmed advocates of press freedom.
Charlie Savage contributed reporting.