With what could be the final legal effort for the WikiLeaks founder, Julian Assange, to avoid extradition to America under way at London, attorney Robert F. Kennedy Jr. is demanding that Mr. Assange be pardoned and his presidential campaign is calling into question President Trump’s “sincerity” in questioning the “security state.”

On Tuesday, Mr. Assange was supposed to attend a hearing at London’s High Court, during which he was supposed to argue in favor of a new appeal of a 2022 decision that he be extradited to America. 

Mr. Assange, who has been held in prison in the United Kingdom since 2019, was too ill to attend the hearing. His lawyers did not elaborate on his condition.

In America, Mr. Assange faces 18 charges — including 17 espionage charges — related to his role in founding and operating WikiLeaks, a website where people could anonymously post classified content, namely documents and videos. If convicted he could face more than 100 years in prison.

In 2010, the website gained notoriety after footage showing an American Apache helicopter killing a dozen people, including two Reuters journalists, at Baghdad was posted online. 

After the website gained the world’s attention, more than 90,000 classified documents relating to the war in Afghanistan and 400,000 relating to the Iraq war were leaked on the website and published in major publications around the world.

American officials have long maintained that Mr. Assange and WikiLeaks endangered Americans by publishing this classified information. Yet one prominent WikiLeaks user, intelligence analyst Chelsea Manning, was released from prison by President Obama in the final days of his term, though she did not receive a presidential pardon.

While Mr. Trump faced criticism for choosing not to pardon Mr. Assange, and President Biden has been silent on the topic as his Department of Justice pushes for extradition, Mr. Kennedy has demanded that Mr. Biden pardon Mr. Assange and has promised to do so in the unlikely event of his election.

“Attacking the messenger is never good policy,” Mr. Kennedy said in a statement. “The government’s war against whistleblowers has turned heroes into criminals. Only if we stand together can we protect free speech.”

Mr. Kennedy’s campaign also began to circulate a petition in support of the release of Mr. Assange Monday, though it had not reached its 300,000 signature goal on Tuesday.

In a statement to the Sun, a spokesman for Mr. Kennedy’s campaign called into question how serious Mr. Trump was in his opposition to what Mr. Trump and his allies often call the “deep state.”

“Trump’s silence on the persecution of Julian Assange calls into serious question his sincerity and ability to overturn the entrenched interests of the American security state,” a spokesman for Mr. Kennedy’s campaign said.

Mr. Kennedy also said that, if elected, on “my first day in office, I will pardon Julian Assange and investigate the corruption and crimes he exposed.”

The move by Mr. Kennedy could be an overture to voters who back the Libertarian Party, an organization that has historically supported pardoning Mr. Assange. When Mr. Assange was arrested in 2019, the Libertarian Party chairman, Nicholas Sarwark, called for the charges against Mr. Assange to be dismissed. 

“This politically motivated prosecution should be dismissed in the interest of justice and to protect our First Amendment,” Mr. Sarwark said, adding that press freedom “should apply to everyone no matter how much of a jerk they are or how uncomfortable their reporting makes the U.S. government.”

The move by Mr. Kennedy also comes as he battles to gain ballot access across the country and may be flirting with seeking the Libertarian Party nomination in order to gain ballot access.

Mr. Trump’s office did not immediately respond to a request for comment from the Sun.