AT&T, Apple, Cisco, and Verizon are all backing Microsoft in a challenge against federal prosecutors who want access to a customer’s email data stored in Ireland. Microsoft has objected to a warrant issued by a US judge, arguing that it may authorize the US government to search Microsoft premises abroad and "reduce the privacy protection of everyone on the planet." The warrant was originally granted in December, but Microsoft objected as the customer’s emails are stored in Ireland, outside the reach of a domestic search warrant.

Verizon is backing Microsoft’s concerns, and AT&T has also filed its own support, noting that "this practice rests on an understanding that when it comes to data storage and privacy protections, location matters." Apple and Cisco have both filed their support together. Microsoft argues that online warrants should be subject to the equivalent of physical world warrants, based on location. The Justice Department believes Microsoft’s approach could be "a dangerous impediment to the ability of law enforcement to gather evidence of criminal activity."

A key case for the trust of Microsoft cloud customers

It’s a key case, especially given Microsoft’s unpredecented response to concerns of NSA data access earlier this year, offering customers in foreign countries the option of having their data stored outside US borders. Microsoft and other US technology companies are trying to take steps to reassure customers that they don’t freely cooperate with the US government, following a series of leaks from former NSA contractor Edward Snowden. For a "mobile first, cloud first" focused Microsoft, winning customers and their trust for its cloud services is an important part of the company’s future.

Update (June 16th): Cisco and Apple have both filed for support of Microsoft's case. The article has been updated to reflect this.