MELISSA BLOCK, HOST:
The FBI review of emails between former CIA Director David Petraeus and his mistress Paula Broadwell is raising big questions about Big Brother. Among them: When can federal law enforcement review a person's private communications? NPR's Carrie Johnson have some answers.
CARRIE JOHNSON, BYLINE: To Julian Sanchez, a research fellow at the Cato Institute, the real scandal over the Petraeus affair is not sex, it's the invasion of privacy.
JULIAN SANCHEZ: Law enforcement and certainly intelligence agencies have an incredible amount of ability to gather huge volumes of detailed information about people's most Internet online communications, a lot of it without requiring a full-blown warrant, a lot of it without requiring even any kind of judicial approval.
JOHNSON: The 1986 Electronic Communications Privacy Act says emails in transit to the recipient or unopened messages are highly protected. But it also allows law enforcement to get opened messages and emails older than six months. All an agency like the FBI needs is a subpoena or an order saying the emails are relevant to an ongoing criminal investigation. Julian Sanchez.
SANCHEZ: Given the weakness of the initial case here, given the fact that it now seems that the initial impetus for this investigation was not actually a crime, you have to wonder, well, were they able to get access to some of these older emails in part because they didn't have to show probable cause that a crime had been committed?
JOHNSON: Former computer crimes prosecutor Orin Kerr says he believes investigators in the Petraeus affair must have gotten court permission to review the Gmail messages.
ORIN KERR: In terms of email privacy, the basic idea is that the government can get the contents of email accounts, much like they can get search warrants to search homes. The big difference is that when the government search your home, you probably know about it.
JOHNSON: So, Kerr says, just because you do it in private email account doesn't mean it's a secret. Carrie Johnson, NPR News, Washington.