Twitter just filed its brief appealing a June decision by a New York criminal court judge requiring the company to give the Manhattan District Attorney detailed information on the communications of Twitter user Malcolm Harris, an Occupy Wall Street protester charged with disorderly conduct in connection with a march on the Brooklyn Bridge.

As we did before, the ACLU will file a friend-of-the-court brief in support of Twitter. You can find Twitter’s brief from today here; the ACLU’s brief will be available here later today. Last week, Harris filed his own appeal as well.

It was great news when Twitter filed its own motion in May to quash the DA’s subpoena after the court ruled that Harris had no standing to challenge the subpoena. Twitter should be commended for taking that bold step. But Twitter shouldn’t have even been forced to take it.

Under the First and Fourth Amendments, we have the right to speak freely on the Internet, safe in the knowledge that the government cannot obtain information about our communications or our private information unless law enforcement first satisfies First Amendment scrutiny and obtains a warrant showing probable cause. The DA didn’t do that here. Instead, it has tried to avoid these constitutional hurdles by issuing a mere subpoena for Harris’s Twitter information.

The courts shouldn’t permit this. The information demanded by the DA includes not only the contents of Harris’s tweets, but his private subscriber information – including the IP addresses he used to access Twitter over three-plus months, which can reveal his physical location throughout that entire period. The government also asked for the date, time, and duration of each of his Twitter sessions. By denying Twitter’s and Harris’s challenge, the court held that the government can access this wealth of sensitive personal information without satisfying basic constitutional protections. That isn’t right.

Just as disturbing, the court affirmed its earlier ruling that people like Harris can’t even go to court to protect their own constitutional rights when it comes to the Internet because, according to the court, we give up our constitutional rights whenever we provide information to a third-party Internet service like Twitter.

As we discuss in our friend-of-the-court brief, that holding is contrary to decisions from the U.S. Supreme Court and other courts around the country. Those cases make clear that individuals whose constitutional rights are implicated by government requests for information to third parties (such as Twitter) have standing to challenge those requests. That principle must apply to Internet activities as well. Although Twitter has admirably defended its user’s rights in this case, we cannot expect that Internet companies will have either the resources or the incentives to go to court over every one of the thousands of government subpoenas that they receive.

We’re hopeful that Twitter’s appeal will overturn the criminal court’s dangerous decision, and reaffirm that we retain our constitutional rights to speech and privacy online, as well as offline.

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