A federal magistrate in Kansas has ruled in In the Matter of Applications for Search Warrants for Information Associated With Target Email Address that the government must use a search warrant to obtain any stored electronic communications, contrary to the Electronic Communications Privacy Act. Even more significantly, the magistrate determined that the typical warrant used by law enforcement for electronic communications -- which demands all communications associated with a particular account -- is invalid for lack of particularity. Rather, the magistrate ruled, the warrant must state with specificity which emails are to be disclosed so that the communications provider can separate the communications relevant to the crime under investigation from purely innocent communications. This is the first reported decision to apply the Fourth Amendment’s particularity requirement in this way. If upheld, it would deal a sharp blow to the government’s longstanding method of seeking communications content from providers. Ironically, by limiting the government to only specified categories of email, the decision could impose new burdens on communications providers, since it would likely be left to them to sort through all the emails in an account to determine which ones fit the specific criteria set out in a warrant.