But the 5-4 ruling in Branzburg v. Hayes also has bedeviled generations of prosecutors, media lawyers and judges because one of the five justices in the majority, Lewis Powell, wrote a concurring opinion that suggested that maybe the court's holding was not as absolute as it sounded. Powell said courts would consider the competing claims of prosecutors and journalists case by case, and called judges to strike "a proper balance between freedom of the press and the obligation of all citizens to give relevant testimony with respect to criminal conduct."
At the time, Justice Potter Stewart charitably referred to Powell's opinion as "enigmatic" and hoped that it would lead to "a more flexible view in the future."
Last year, Judge Albert Diaz, a member of a federal appeals court panel that is weighing an effort to compel a reporter's testimony in an investigation of unauthorized disclosure, called the 1972 ruling "clear as mud." The panel of the 4th U.S. Circuit Court of Appeals in Richmond, Va., has yet to rule on the attempt by New York Times journalist James Risen to avoid testifying at the trial of former CIA officer Jeffrey Sterling. Sterling is accused of leaking classified information about a botched covert operation in Iran.
Earlier, U.S. District Judge Leonie Brinkema, the trial judge handling Sterling's case, sided with Risen, saying, "A criminal trial subpoena is not a free pass for the government to rifle through a reporter's notebook."
Other courts, though, recently have rejected journalists' attempts to quash subpoenas for their testimony.
The rules governing how the government seeks other information such as emails haven't kept up with the pace of technology. When it comes to electronic records held by Internet service providers, technology companies and credit card companies, the rules "are not as strict as they are for news media telephone toll records," said Alan Butler, appellate advocacy counsel for the Electronic Privacy Information Center.