Microsoft has just made public its court filings objecting to demands by the U.S. government that the company turn over email files that are located on servers outside the U.S.
Microsoft has declined to provide the emails saying that a search warrant isn't valid outside the territory of the United States. In response, the U.S. Department of Justice claims that the warrant served on Microsoft isn't really a warrant at all, but rather a "hybrid" of a warrant and a subpoena. In response, Verizon has filed a brief in support of Microsoft.
If all of that seems like slightly insane legal logic, there's a reason. It is slightly insane and to demonstrate I'll explain in more detail. Late in 2013, Microsoft was presented with a demand for information about one of its users of Outlook.com. The company provided the information that was available on U.S. servers, but balked at providing information on servers located overseas.
Microsoft's objection went before a federal magistrate in New York who agreed with the government that Microsoft should provide the information and also comply with the government's insistence that the subject of the investigation not be informed of the delivery of the data. Microsoft responded that to comply with the government's demands would violate the U.S. Constitution in addition to a number of treaties and international agreements.
Part of the problem stems from the fact that the government is treating the data demand as a warrant, such as a search warrant, but under U.S. law a warrant can only be enforced in the United States. There's also a means of gathering information with a subpoena, which could produce information from an overseas location, but a subpoena requires that the subject of the investigation be notified of the subpoena and have a chance to block the subpoena in court.
To get around this, the DoJ is claiming that the demand is a hybrid of both a subpoena and a warrant based on the legal authority conferred by the Electronic Communications Privacy Act of 1986. However, a close reading of the ECPA does doesn't include any wording to support the existence of a hybrid demand, but instead refers to traditional warrants.
In its argument, the DoJ then claims that Congress really intended to mean a hybrid even if it didn't say so. A check of the Congressional Record does not reveal any discussion or definition of a hybrid warrant-subpoena.
Currently, email storage is covered by several different laws and depending on several factors may be subject to either a warrant or a subpoena. The Electronic Privacy Information Center has a chart that illustrates this. Nowhere on the chart is there a provision for some sort of hybrid warrant.