LONDON (AP) — An American constitutional law expert said Thursday that the United States indicted WikiLeaks founder Julian Assange under an “extraordinarily broad” spying law that has been used in the past for politically motivated prosecutions.

Speaking during Assange’s extradition hearing in London, human rights lawyer Carey Shenkman called the century-old Espionage Act “one of the most contentious laws in the United States.”

Shenkman, who co-wrote a book on the history of the act, testified as a witness for Assange, 49, who is fighting his extradition from the U.K. to the U.S.

U.S. prosecutors indicted Assange on 17 espionage charges and one charge of computer misuse over WikiLeaks’ publication of secret American military documents a decade ago. The charges carry a maximum sentence of 175 years in prison.

Assange’s defense team argues that he is a journalist and entitled to First Amendment protections for publishing leaked documents that exposed U.S. military wrongdoing in Iraq and Afghanistan. His lawyers say he is facing a politically motivated prosecution that will stifle press freedom and put journalists around the world at risk.

Shenkman also said in a written witness statement that the administration of President Donald Trump “has prosecuted disclosures of national security information more aggressively than any presidency in U.S. history.”

He said there were eight Espionage Act prosecutions of media sources during former President Barack Obama’s two terms — more than any previous administration — and eight in less than four years under Trump.

Shenkman said there has never been a successful prosecution of a publisher under the act, although there have been attempts, including over the 1971 “Pentagon Papers” leak of documents about the Vietnam War. Leaker Daniel Ellsberg faced 12 Espionage Act charges and faced up to 115 years in prison, but the charges were dismissed in 1973 because of government misconduct against him.

Ellsberg, one of the most famous whistleblowers in living memory, came to Assange’s defense on Wednesday, telling London’s Central Criminal Court that he and the WikiLeaks founder had “very comparable political opinions.”

The case, which is being held under coronavirus social distancing restrictions, has been plagued by technical glitches as witnesses give evidence by video link. Shenkman testified with a cellphone pressed to his ear after audio problems.

Shenkman acknowledged during a testy cross-examination by Clair Dobbin, a lawyer for the U.S. government, that he was part of a team that represented Assange several years ago. He said it was not relevant to his analysis of the Espionage Act, and noted he was a very junior lawyer at the time.

“In the food chain of lawyers, I was plankton,” he said.

The U.S. government says WikiLeaks put the lives of U.S. informants in conflict zones and others at risk by publishing secret documents.

Defense witness John Sloboda, co-founder of the organization Iraq Body Count, said WikiLeaks was careful to ensure names were removed before publication. He disagreed with a suggestion by a prosecution lawyer that Assange took a “cavalier attitude” to redaction.

Sloboda, who was involved in the publication of the Iraq war papers in 2010, said they “were over-redacted for caution.” He said his group developed software to help speed the process by removing all words that were not in an English dictionary, though he acknowledged it was not perfect.

Assange, who has been embroiled in legal battles for a decade, has been in a British prison since he was ejected from his refuge at the Ecuadorian Embassy in London in April 2019.

The extradition hearing at London’s Old Bailey criminal court is due to last until early October.

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