Since the landmark case, Donziger has faced a series of legal attacks from Chevron and a New York federal judge, who has employed a private law firm linked to the oil company to prosecute him. Earlier this month, he was sentenced to six months in prison for contempt of court, and his request for bail pending his appeal was denied.

Amnesty International and United Nations human rights advocates, along with several U.S. lawmakers, are calling for Donziger’s immediate release.

“Chevron and these two judges, really allies of the fossil fuel industry, are trying to use me as a weapon to intimidate activists and lawyers who do this work,” says Donziger. “I need to be prosecuted by a neutral prosecutor, not by Chevron.”