The U.S. did exactly that with some data Microsoft had stored on Irish servers, which was subpoenaed by an American court. Microsoft lost initially, because while the data was in Europe, the subpoena was only served to Microsoft US, which had access to the data, and could therefore validly be required to hand it over under US law. The appeal is still being litigated [1]. Microsoft is very interested in fighting the case, because they've been heavily advertising cloud services to European customers on the promise that the data will be stored in Europe and accessed only according to European laws. If they lose, they may have to either give up that claim, or move to a more fully segmented model where access credentials to data in EU-based datacenters are restricted to EU-based employees.

[1] https://en.wikipedia.org/wiki/Microsoft_Corporation_v._Unite...