A secret U.S. intelligence court has ordered the Justice Department to declassify court documents from 2008 that reportedly outline Yahoo's arguments against turning over customer data to government investigators.

The Foreign Intelligence Surveillance Court, which oversees domestic surveillance of foreign nationals in largely secret proceedings, agreed to Yahoo's request to release its official ruling and legal briefs filed in the 2008 case. In that case, Yahoo reportedly objected to federal demands for customer data, arguing that such requests violated its customers' constitutional protection against warrantless searches.

It is not clear whether the 2008 case specifically involved the reported National Security Agency surveillance program known as PRISM, in which Internet companies like Yahoo have reportedly provided broad data access to the government. The Washington Post reported last month that PRISM enlisted its first corporate partner—Microsoft—in May 2007.

In any event, the intelligence court's 2008 ruling reportedly rejected Yahoo's argument and compelled it to comply with federal data requests. But that order, along with the pro and con arguments raised by parties in the case, were subsequently classified. Yahoo, in fact, couldn't even disclose the fact that it was a party in the case until last month.

The Daily Dot first reported news of the court's declassification decision. The Web site notes that Yahoo's victory is only the second known civilian win before the intelligence court.

The government has until the end of the month to review the documents, and can redact parts it deems "properly classified information." As of this moment, Yahoo is the only major tech company known to have legally objected to government surveillance efforts, although others could conceivably remain bound by gag orders similar to the one that silenced Yahoo until recently.