A ruling by the 6th US Circuit Court of Appeals on Tuesday mandated that the government will need to get a warrant based on probable cause in order to compel an internet service provider to hand over emails of customers.

“The Fourth Amendment must keep pace with the inexorable march of technological progress, or its guarantees will wither and perish.”

The decision covers only Kentucky, Michigan, Ohio, and Tennessee but may rise to the Supreme Court for a farther-reaching decision. Privacy groups are applauding the decision. The case came about after the owner of an herbal supplement company complained that his ISP handed over emails without a warrant. The only policy governing this kind of thing had been the 1986 Stored Communications Act but email has changed a lot since then. At the time, very little email was stored on ISP servers, now pretty much all of it is stored remotely or on the cloud.