CIA operative Jeffrey Sterling is set to begin trial in September after allegedly leaking classified information that appeared in New York Times reporter James Risen's book.
In 2006 Risen wrote the book "State of War," in which he described a CIA plan to sabotage Iran's nuclear program with a Russian agent.
He has been subpoenaed by federal prosecutors to testify at Sterling's case. Sterling's trial is one of five current cases over leaked government information. The Obama administration has aggressively sought to stem the flow of government secrets to the public.
Risen plans to fight the subpoena and told The Washington Post, "I will always protect my sources, and I think this is a fight about the First Amendment and the freedom of the press."
Steven Aftergood, Director of the Project on Government Secrecy at the Federation of American Scientists, said to the Post that "the subpoena to Risen significantly ups the ante. It threatens to turn the administration's fight against leaks into a broader assault on the press."
The government "seeks to strike the proper balance between the public's interest in the free dissemination of information and effective law enforcement," Justice Department spokeswoman Laura Sweeny said in defense of Obama's administration.
