In a landmark decision issued today in the criminal appeal of U.S. v. Warshak, the Sixth Circuit Court of Appeals has ruled that the government must have a search warrant before it can secretly seize and search emails stored by email service providers.
Closely tracking arguments made by EFF in its amicus brief, 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.

EFF filed a similar amicus brief with the 6th Circuit in 2006 in a civil suit brought by criminal defendant Warshak against the government for its warrantless seizure of his emails. There, the 6th Circuit agreed with EFF that email users have a Fourth Amendment-protected expectation of privacy in the email they store with their email providers, though that decision was later vacated on procedural grounds. Warshak's appeal of his criminal conviction has brought the issue back to the Sixth Circuit, and once again the court has agreed with EFF and held that email users have a Fourth Amendment-protected reasonable expectation of privacy in the contents of their email accounts.