For years, the Justice Department has been conducting surveillance on computer networks like Facebook, or sending National Security Letters (NSLs) to obtain emails from Apple, Microsoft, and Google. Various national security laws (including the PATRIOT Act) prevent the companies that operate those networks from disclosing the fact that they've even received a NSL.
Twitter is fed up with this secrecy. Yesterday, Twitter sued the DOJ alleging "prior restraint" -- i.e., censorship -- in that Twitter is being forced to refrain from speaking about how many NSLs it's received.
A Compromise -- of Sorts
Back in January, DOJ reached a settlement with several tech companies about their disclosure of NSLs: Yahoo, Microsoft, Google, LinkedIn, and Facebook. Under the terms of the settlement, any tech company would be able to describe how many NSLs they've received in "bands" of 1,000 or 250. So Microsoft could say, "This year, we received between 251 and 500 requests," but that's as specific as they could get.
Twitter isn't satisfied with this compromise and instead wants to be more transparent -- including the ability to say that it received zero NSLs (currently, the DOJ won't let a provider say that they've received zero NSLs or FISA requests).
Though Twitter's complaint throws the book of free speech terms at the DOJ -- including prior restraint and viewpoint discrimination -- really, this will come down to prior restraint and national security.
Prior Restraint and National Security
Framing the argument as one of prior restraint works in Twitter's favor, as a prior restraint "[bears] a heavy presumption against its constitutional validity," the Supreme Court said in New York Times v. United States (a.k.a. the "Pentagon Papers" case). The problem for Twitter is that it's not "the press" in the traditional sense; neither it nor its users are routinely engaged in the business of reporting news. (It's true that many Twitter users do that, but they also post pictures of their breakfast.)
Also notable in New York Times was the fact that the Pentagon Papers didn't really concern the active prosecution of the war; rather, they were an internal Department of Defense history of the war. The NSLs at issue in the Twitter case concern investigations that may or may not still be ongoing.
That's a Busy Court
One thing Twitter has going for it: The most recent case in the Northern District of California to deal with NSLs found them to be unconstitutional. The facts of In re National Security Letter are vague -- we don't know who the petitioner was or what, specifically, the petitioner wanted, but that party made many of the same claims that Twitter does here.
Currently, In re National Security Letter is on appeal to the Ninth Circuit. It's certainly going to be a test for the likelihood that Twitter v. Holder will succeed.