According to CNET:
The U.S. Department of Justice and the FBI believe they don't need a search warrant to review Americans' e-mails, Facebook chats, Twitter direct messages, and other private files, internal documents reveal.
Government documents obtained by the American Civil Liberties Union and provided to CNET show a split over electronic privacy rights within the Obama administration, with Justice Department prosecutors and investigators privately insisting they're not legally required to obtain search warrants for e-mail. The IRS, on the other hand, publicly said last month that it would abandon a controversial policy that claimed it could get warrantless access to e-mail correspondence.
The U.S. attorney for Manhattan circulated internal instructions, for instance, saying a subpoena -- a piece of paper signed by a prosecutor, not a judge -- is sufficient to obtain nearly "all records from an ISP." And the U.S. attorney in Houston recently obtained the "contents of stored communications" from an unnamed Internet service provider without securing a warrant signed by a judge first.
"We really can't have this patchwork system anymore, where agencies get to decide on an ad hoc basis how privacy-protective they're going to be," says Nathan Wessler, an ACLU staff attorney specializing in privacy topics who obtained the documents through open government laws. "Courts and Congress need to step in."
The Justice Department's disinclination to seek warrants for private files stored on the servers of companies like Apple, Google, and Microsoft continued even after a federal appeals court in 2010 ruled that warrantless access to e-mail violates the Fourth Amendment. A previously unreleased version of an FBI manual (PDF), last updated two-and-a-half years after the appellate ruling, says field agents "may subpoena" e-mail records from companies "without running afoul of" the Fourth Amendment. . . .
Not all U.S. attorneys have attempted to obtain Americans' stored e-mail correspondence without a warrant. The ACLU persuaded a judge to ask whether warrantless e-mail access has taken place in six of the 93 U.S. Attorneys' offices -- including the northern California office that's prosecuted an outsize share of Internet cases. The answer, according to assistant U.S. attorney Christopher Hardwood, was "no."
Still, the position taken by other officials -- including the authors of the FBI's official surveillance manual -- puts the department at odds with a growing sentiment among legislators who insist that Americans' private files should be protected from warrantless search and seizure. They say the same Fourth Amendment privacy standards that require police to obtain search warrants before examining hard drives in someone's living room, or a physical letter stored in a filing cabinet, should apply.
After the IRS's warrantless e-mail access policy came to light last month, a dozen Republican and Democratic senators rebuked the agency. Their letter (PDF) opposing warrantless searches by the IRS and signed by senators including Mark Udall (D-Colo.), Mike Lee (R-Utah), Rand Paul (R-Ky.), and Ron Wyden (D-Ore.) said: "We believe these actions are a clear violation of the Fourth Amendment's prohibition against unreasonable searches and seizures."
Steven Miller, the IRS' acting commissioner, said during a Senate hearing that the policy would be changed for e-mail. But he left open the possibility that non-email data -- Google Drive and Dropbox files, private Facebook and Twitter messages, and so on -- could be accessed without a warrant. . . .