For the last year Microsoft has been fighting a legal battle over the right of the United States government to issue warrants for data stored in its overseas datacenters, specifically the company's datacenter in Dublin, Ireland. As of right now Microsoft has lost every major case in this contest, so the decision to keep fighting on behalf of their users is admirable.
The US Government claims that because Microsoft is a corporation based in the US, the Department of Justice has jurisdiction to issue subpoenas and warrants for data hosted by Microsoft, regardless of where the bits themselves physically reside. Microsoft argues otherwise, that as an international company with holdings all over the world the data it stores in Ireland, or other countries, should be subject to those nations laws instead of US law.
This is important, as the eventual outcome of this case will determine how easy it is for the US government to gain access to data stored by American corporations, currently a hot topic around the world. In this case, Microsoft is fighting on behalf of all its international customers who rightly believe they are outside the legal jurisdiction of the US.
Brad Smith, Microsoft's General Counsel & Executive Vice President, Legal and Corporate Affairs had this to say about what his company claims is legal overreach by the US government
In the U.S. we believe there is an important debate to be held about the best way to reform the law and our international relationships, and there are critical policy considerations on both sides. Law enforcement needs to be able to do its job, but it needs to do it in a way that respects fundamental rights, including the personal privacy of people around the world and the sovereignty of other nations. We hope the U.S. government will work with Congress and with other governments to reform the laws, rather than simply seek to reinterpret them, which risks happening in this case
He also goes on to mention specific bodies of law, such as the Mutual Legal Assistance Treaties that require modernization to better fit within our modern world. He believes that Congress did not intend for any law they have written to expand the "geographic reach of search warrants".
It is clear that Microsoft intends to continue fighting this attempt to broaden the scope of US jurisdiction, however it is not clear what the outcome of this will be as one federal court has already ruled against them after appealing the district decision.