Territoriality will continue to be one of the most vexing problems for data regulation in 2018.  One aspect of this debate relates to whether a U.S. judge can compel the disclosure of personal data located in Europe without using international treaty mechanisms.  This issue is currently being considered by the United States Supreme Court in the case United States v. Microsoft.  The case involves the question of whether a U.S. statute relating to search warrants can be interpreted as extending to a search for data located outside the United States; in this case, the data is located in Ireland.  The U.S. Court of Appeals found that, in the absence of express wording in the statute relating to extraterritorial application, the statute should be interpreted as being limited to searches conducted within the territory of the United States.  The Supreme Court is currently reviewing the case.  In December, 2017, the European Commission filed an amicus brief urging the Supreme Court to give due consideration to the principles of international comity and territoriality when interpreting the U.S. statute.

According to the European Commission:

“any domestic law that creates cross-border obligations – whether enacted by the United States, the European Union, or another state – should be applied and interpreted in a manner that is mindful of the restrictions of international law and considerations of international comity.  The European Union’s foundational treaties and case law enshrine the principles of ‘mutual regard to the spheres of jurisdiction’ of sovereign states and the need to interpret and apply EU legislation in a manner that is consistent with international law.”