Microsoft, one of the world's largest e-mail providers, is resisting a government search warrant to compel the firm to turn over customer data held in a server located overseas.
Specifically, hosted in a datacenter in Dublin, Ireland. This is an entirely novel legal argument, however.
Microsoft argues that for data held overseas, the U.S. government should abide by its mutual legal assistance treaties, or MLATs. Those are agreements between the United States and foreign countries that typically require the requesting government to be in compliance with the other government's laws. Irish law requires authorization from an Irish district court judge to obtain e-mail content from a provider.
Seems pretty obvious that since we have chosen to comply with EU data protection regulations by hosting European users' data in Ireland, that data should be subject to the legal protections of those regulations.