WikiLeaks says its founder Julian Assange will turn himself in to U.S. authorities under one condition: Chelsea Manning must get clemency.

“If Obama grants Manning clemency, Assange will agree to U.S. prison in exchange—despite its clear unlawfulness,” the company wrote in a Tweet that linked to a document calling for more transparency in the U.S. Justice Department’s investigation into WikiLeaks. Assange’s lawyer Barry Pollack signed the document.

Manning is currently serving a 35-year prison sentence for leaking classified information to WikiLeaks in May 2010, which included a video of a Baghdad airstrike.

 

Assange has been holed up in the Ecuadorian embassy in London since 2012. And despite the Swedish government’s repeated calls for his arrest over allegations of rape, the WikiLeaks editor-in-chief has refused to leave out of fear it will result in his deportation to the U.S.

That said, the U.S. government does not currently want Assange. He hasn’t been charged with any crime, though Assange’s lawyer suggests the U.S. Justice Department is conducting a criminal investigation.

 

It’s possible, of course, that the U.S. government has already obtained an indictment against Mr. Assange for violating laws concerning the disclosure of classified information (and that such an indictment remains sealed), but there’s certainly no public evidence that he currently faces charges—and so no obvious explanation for what ‘turning himself in’ would accomplish,” Stephen Vladeck, a professor of law at the University of Texas School of Law in Austin, told Fortune in an email.

Without a charge, it’s possible Assange could only be legally held for 48 hours. But if officials initiate immigration proceedings against Assange, showing that he is dangerous, the U.S. could hold Assange for longer, according to Vladeck.

For now, it looks like WikiLeaks has made an empty promise.