Warrants? We don’t need no stinking warrants.

According to new documents obtained by the American Civil Liberties Union, government officials may not always obtain warrants when they snoop through our emails, Facebook messages, and other electronic communications -- and the FBI apparently doesn’t even believe it’s legally required to do so.

The documents, which were obtained through a Freedom of Information Act request and posted on the ACLU website, suggest that the U.S. Department of Justice is flouting a 2010 federal appeals court ruling that declared warrantless access to email a violation of the Fourth Amendment.

That ruling, a criminal appeal of U.S. v. Warshak, stated that the government must obtain a warrant before it can secretly seize and search emails stored by email service providers. As the Electronic Frontier Foundation noted at the time, “the court found that email users have the same reasonable expectation of privacy in their stored email as they do in their phone calls and postal mail.”

However, an FBI “Operations Guide” -- made public for the first time by the ACLU -- tells a more nuanced story. Revised in June of last year, the guide makes exemptions for email stored by a service provider for more than 180 days. That’s basically any message sitting in your Gmail or Facebook folder for longer than six months. Most email messages are stored on cloud servers, and with virtually unlimited storage space, many email users see no need to delete old messages.

According to the “Operations Guide,” here’s how the FBI views such contents:

“[I]f the contents of an unopened message are kept beyond six months or stored on behalf of the customer after the e-mail has been received or opened, it should he treated the same as a business record in the hands of a third party, such as an accountant or attorney. In that case, the government may subpoena the records from the third party without running afoul of either the Fourth or Fifth Amendment.”

Technically speaking, any commercial email service is a third party. Some email software programs, like Outlook, download messages to users' hard drives. The government needs a warrant to access those messages, because they’re stored on private computers. But based on how the FBI has worded its policy, emails that are stored on servers like Gmail, Hotmail, Yahoo Mail, Facebook messages or any other third party are potentially subject to warrantless access by the government."

In a statement, the FBI insisted its methods are constitutional: “In all investigations, the FBI obtains evidence in accordance with the laws and Constitution of the United States, and consistent with Attorney General guidelines.”

However, that terse justification hasn't quelled the concerns of privacy advocates.

“Our [Freedom of Information Act] request was the FBI’s chance to produce any policy documents, manuals, or other guidance stating that a warrant is always required, but they failed to do so,” wrote Nathan Freed Wessler, an ACLU staff attorney, in a blog post on Wednesday.

Wessler said the documents show that federal policies regarding access to electronic communication are in a “state of chaos,” and that reforms are needed. He cited the Supreme Court’s landmark 1877 Ex Parte Jackson ruling, which established the “secrecy of letters” as a legal concept and denied government officials the authority to snoop through our postal mail without a warrant.

Changes could be on the way, however. In April, the Senate Judiciary Committee began considering revisions to the 1986 Electronic Communications Privacy Act, a move for which large tech companies such as Amazon (NASDAQ:AMZN), Facebook (NASDAQ:FB) and Google (NASDAQ:GOOG) have been lobbying for some time. Reform legislation is working its way through the Senate, and if finalized, it could close the loophole that allows government officials warrantless access to messages stored on third-party servers.

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