Shira Ovide

Microsoft is opposing a US government demand for a user’s emails stored on company computers outside the country, in the latest example of tech companies’ willingness to challenge government information requests in the post-Snowden era.

Microsoft in a court filing dated June 6 said it opposed a search warrant for information on a user’s online emails stored in Microsoft’s Ireland data center.

“Congress has not authorized the issuance of warrants that reach outside US territory,” Microsoft wrote in the filing with US District Court in Manhattan.

Some legal experts said as a US company, Microsoft would have to comply with US court orders for emails or other customer information, whether data was stored in Seattle or Dubai. But Microsoft seems willing to test the patchwork of international laws on control of computerized information.

Long frustrated in efforts to collect payments from some users of its software in China and other emerging markets, Microsoft has enlisted help from an unlikely set of allies: attorneys general in states such as Louisiana and Oklahoma. Attorneys general don't typically get involved in overseas disputes involving companies from outside their state borders. But Microsoft has helped persuade attorneys general that overseas software piracy leads to job losses at manufacturing companies in their states.

That's because foreign manufacturers exporting products to the US can shave business expenses by using stolen software, gaining an unfair cost advantage over American rivals who pay for software, according to Microsoft and its allies, including the National Association of Manufacturers trade group.

The attorney general's office in Oklahoma recently filed suit against a Chinese maker of oil equipment, alleging it was stealing software written by Microsoft and others and gaining a cost advantage over Oklahoma-based competitors. The effort follows similar warning letters or lawsuits -- involving allegations against companies in Asia and Latin America -- filed over the past two years by attorneys general in California, Tennessee, Massachusetts and Washington State.