An appeals court in New York will hold an oral hearing in the Feds vs Microsoft battle today. The so-called Microsoft warrant case has dragged on for nearly two years as Redmond resists efforts to make it hand over customer emails stored in Ireland.

The American Justice Department wants the emails as part of a drug-trafficking investigation, and judge Loretta Preska ruled in July 2014 that Microsoft should hand them over regardless of where they are stored because it has "control" over them.

However, Microsoft maintains that the data is secured under EU data protection laws.

Part of the problem is that an existing international agreement would have allowed the US to contact the Irish authorities to gain access to the emails through legal means via a Mutual Legal Assistance Treaty (MLAT).

But, to the Irish government’s annoyance, the American court instead decided to cut Ireland out of the equation.

Last December, Ireland reminded the New York court: "Ireland is an internationally-recognised sovereign nation state ... and does not accept any implication that it is required to intervene into foreign court proceedings to protect its sovereignty."

Concerned that unilateral American government access to data stored in Europe could frighten off European business, 30 tech companies including Verizon, Apple, Amazon, Cisco, Salesforce, HP, eBay, Infor, AT&T and Rackspace, have directly or indirectly weighed in on the side of Microsoft. ®