United States v. Warshak, 631 F.3d 266 (6th Cir. 2010) (full-text).
Warshak was being investigated for a scheme to defraud customers of his company. The government sought and obtained permission from Warshak's ISP to preserve the contents of Warshak's e-mails, and eventually the government was permitted access to approximately 27,000 e-mails. Warshak moved to suppress this access as forbidden under the Fourth Amendment absent a warrant.
Appellate Court Proceedings
The Court held that the contents of the e-mails were protected under the Fourth Amendment. The court compared e-mails to physical mail, observing that "[g]iven the fundamental similarities between e-mail and traditional forms of communication, it would defy common sense to afford e-mails lesser Fourth Amendment protection."
|“||The government may not compel a commercial ISP to turn over the contents of a subscriber's e-mails without first obtaining a warrant based on probable cause. Therefore, because they did not obtain a warrant, the government agents violated the Fourth Amendment when they obtained the contents of Warshak's e-mails. Moreover, to the extent that the SCA purports to permit the government to obtain such e-mails warrantlessly, the SCA is unconstitutional.||”|
The panel noted the importance of e-mail as an "indispensable part" of modern society. The panel held that "if government agents compel an ISP to surrender the contents of a subscriber's e-mails, those agents have thereby conducted a Fourth Amendment search, which necessitates compliance with the warrant requirement absent some exception."