I have just posted a new draft paper entitled "Cross-Border Evidence Gathering in Transnational Criminal Investigation: Is the Microsoft Ireland Case the 'Next Frontier'?" The paper examines the currently roiled state of international law regarding the gathering of electronic evidence across borders by law enforcement officials. It specifically bears down on the issue of what are sometimes called "long-arm subpoenas," essentially demands by police in one state that individuals located in that state gather and produce evidence that is stored or otherwise located in another state. This has traditionally been an irritant between states but has become all the more relevant with regard to electronic data.
The issue has come to a head in the U.S. in the case of US. v. Microsoft, where police issued a warrant demanding that Microsoft produce data that was stored at its facility in Ireland. Microsoft refused on the basis that the warrant had inappropriate extraterritorial reach; both Irish sovereignty and Irish/EU law could be breached if Microsoft complied with the request. The Second Circuit Court of Appeals agreed with Microsoft, in a decision which will likely be appealed to the US Supreme Court but which dealt almost entirely with US procedural law and did not satisfactorily address the international law aspects (despite the fact that these were argued very ably by Microsoft and some of the interveners).
My paper focuses on the international law angle, in particular the customary international law prohibition on the extraterritorial exercise of enforcement jurisdiction. It concludes that, despite the fact that state practice is uneven, the best conclusion is that long-arm subpoenas breach the prohibition, and that effective solutions to this problem have to involve multilateral agreement of some kind.
The paper is under submission to a journal but the current working version can be found on SSRN here; the abstract is below. I welcome comments!
"Cross-Border Evidence Gathering in Transnational Criminal Investigation: Is the Microsoft Ireland Case the 'Next Frontier'?"
ABSTRACT: A recent and prominent American appeals court case has revived a controversial international law question: can a state compel an individual on its territory to obtain and produce material which the individual owns or controls, but which is stored on the territory of a foreign state? The case involved, United States v. Microsoft, features electronic data stored offshore which was sought in the context of a criminal prosecution. It highlights the current legal complexity surrounding the cross-border gathering of electronic evidence, which has produced friction and divergent state practice. The author here contends that the problems involved are best understood—and potentially resolved—via examination through the lens of the public international law of jurisdiction, and specifically the prohibition of extraterritorial enforcement jurisdiction. Analysis of state practice reveals that unsanctioned cross-border evidence gathering is viewed by states as an intrusion on territorial sovereignty, engaging the prohibition, and that this view properly extends to the kind of state activity dealt with in the Microsoft case.