Julian Assange faces up to five years in prison for his role in “one of the largest compromises of classified information in the history of the United States,” federal officials said today in unsealing a March 2018 indictment against the WikiLeaks founder.

Assange, 47, was arrested Thursday in the United Kingdom after Ecuador revoked the asylum he had enjoyed in its London embassy since 2012. British authorities detained him for jumping bond in a sexual assault case, but that charge was immediately eclipsed by a U.S. request to extradite him to face a conspiracy charge in the incident that made Assange notorious: the 2010 release of hundreds of thousands of U.S. military documents and State Department diplomatic cables related to the wars in Afghanistan and Iraq.

“Assange engaged in a conspiracy with Chelsea Manning, a former intelligence analyst in the U.S. Army, to assist Manning in cracking a password stored on U.S. Department of Defense computers connected to the Secret Internet Protocol Network (SIPRNet),” the Justice Department bulletin alleges. Neither the bulletin nor the indictment says Assange was successful in cracking the password.

Assange will have an opportunity to fight his extradition to the U.S. in a British court, but it will be an uphill battle. A 2011 British report on the U.S.-U.K. extradition treaty found that Britain denied only 10 requests out of 130 reviewed.

The indictment, filed in U.S. District Court for the Eastern District of Virginia, Alexandria Division, states that Assange encouraged Manning, then known as Bradley Manning and stationed in Iraq, to release a number of databases including classified information for posting on the WikiLeaks website. "These databases contained approximately 90,000 Afghanistan war-related significant activity reports, 400,000 Iraq war-related significant activity reports, 800 Guantanamo Bay detainee assessment briefs, and 250,000 U.S. Department of State cables."

The disclosures turned WikiLeaks into “a competitor to news media and intelligence agencies,” as Time magazine put it when it named Assange a runner-up for 2010 Person of the Year. Assange went on to collaborate with National Security Agency contractor Edward Snowden to release information in 2013 on the agency’s bulk collection of phone metadata from Americans — as well as classified information on foreign surveillance, such as U.S. successes in spying on Russian government officials.

WikiLeaks' releases raised complicated legal and political questions. Assange’s defenders hailed him as a champion of privacy rights and transparency, but his popularity faded in 2016, when WikiLeaks published emails stolen from Hillary Clinton’s campaign as part of Russia’s interference in the presidential elections.

“Julian Assange has long professed high ideals and moral superiority,” Sen. Mark Warner, D-Va., said Thursday. "Unfortunately, whatever his intentions when he started WikiLeaks, what he’s really become is a direct participant in Russian efforts to undermine the West and a dedicated accomplice in efforts to undermine American security. It is my hope that the British courts will quickly transfer him to U.S. custody so he can finally get the justice he deserves.”

Some observers argue that punishing him for disclosing government secrets could set a legal precedent for the prosecution of journalists. "Images of Ecuador's ambassador inviting the UK's secret police into the embassy to drag a publisher of--like it or not--award-winning journalism out of the building are going to end up in the history books,” Snowden tweeted Thursday. “Assange's critics may cheer, but this is a dark moment for press freedom.”

Justice Department officials sidestepped that issue in the indictment by charging Assange, not for publishing the classified documents, but for his direct role in hacking U.S. government networks.

“On or about March 8, 2010, Manning provided Assange with part of a password stored on United States Department of Defense computers connected to the secret internet protocol network,” the indictment says. “On or about March 10, 2010, Assange requested more information from Manning related to the password. Assange indicated that he had been trying to crack the password by stating that he had had ‘no luck so far.’”

Assange lost his place of refuge in the Ecuadorian Embassy after the government accused Assange of violating the terms of his asylum. Ecuadorian officials blame WikiLeaks for the release of documents that led to a corruption probe against President Lenín Moreno.