Raising the stakes in the government’s battle with Occupy Wall Street, Manhattan District Attorney Cy Vance has subpoenaed the Twitter account of an Occupy supporter who was one of the approximately 700 protesters arrested while crossing the Brooklyn Bridge on October 1, 2011. Malcolm Harris was charged with disorderly conduct, a violation that is not a crime per se, but is the lowest level offense in the New York State Penal Law.

Harris, a 23-year-old writer, has been alerted by Twitter’s San Francisco offices that they have received a subpoena from the New York prosecutor, seeking “any and all user information including e-mail address, as well as any and all tweets for the period 9/15/11-12/31/11” for his account.

According to a complaint signed by Police Officer Thomas Manning, Harris, “with intent to cause public inconvenience, annoyance and alarm and recklessly creating a risk thereof, obstructed vehicular and pedestrian traffic.” While Manning did not observe any of this himself, he was informed by a Sgt. Brian Byrnes that Harris was “standing in a group of approximately six-hundred individuals in the traffic lane of the above-listed location…[and] obstructed vehicular traffic and created a public disturbance/inconvenience in that it prevented all vehicles from being able to use the roadway.”

To prove the disorderly conduct charge against Harris requires the prosecution to establish only the allegations in the complaint—that is, that at the time and place of the arrest, he was present in the roadway and intentionally interfered with traffic. They would not need the contents of months of Tweets, including any private direct messages, and Harris’s e-mail address (which would then enable them to subpoena Harris’s e-mail service provider) to meet their burden of proof.

Twitter maintains both the content of subscribers’ communications and records relating to them and the use of their accounts. The privacy policy describes the services as “primarily designed to help you share information with the world. Most of the information you provide us is information you are asking us to make public.… You should be careful about all information that will be made public by Twitter, not just your Tweets.” The Twitter website states that the company will inform the target of a subpoena whose records have been demanded by a government agency. Following its protocol, Twitter did not honor the prosecutor’s demand that it “not disclose the existence of this subpoena to any party.” The subpoena goes on to say, “Such disclosure would impede the investigation being conducted and interfere with the enforcement of law.”

According to Aden Fine, senior staff attorney at the ACLU, the federal Electronic Communications Privacy Act requires that a government agency seeking access to a subscriber’s account must give notice to the subscriber, and when seeking content is probably required to obtain a warrant. This failure to comply with federal law, Stolar argues, makes the subpoena defective. He cites numerous other improprieties, such as the DA’s office’s simply faxing the document signed by Lee Langston, an assistant to the District Attorney, along with a cover letter signed by a clerk. But no judge’s name or signature appears anywhere, and the DA was required to give Harris notice and probably to have secured a warrant. Stolar also attacks the subpoena as “overly broad,” seeking content and records for three and a half months, for personal as well as public tweets, and because it does not specify what information the prosecutor is looking for. Finally, a trial subpoena is not meant as a tool of investigation, though this subpoena clearly ordered Twitter not to interfere with the investigation.

“Law enforcement appears to regularly be sending subpoenas to Twitter,” says Fine, adding that it’s likely that other social networks are receiving them as well, as government seeks more information about Internet activity, and are not notifying the subscriber. In federal cases, the government may request that a judge issue a “gag order,” so that the social network site cannot notify its subscriber. Both federal and state prosecutors may want not content, but information about where a subscriber was at a particular time, for a typical criminal case. What is unprecedented about Harris’s subpoena is that he learned about it.

Especially troubling, Fine says, is that the prosecutor often seeks more than the subscriber’s identity, e-mail address and other identification; here they want the content of the transmissions, including private messages, so that both the First and Fourth Amendments to the Constitution are unprotected.

Why the prosecutor would bother to conduct an investigation into the most minor of offenses, one that even upon conviction does not result in a criminal record is unclear. But whatever it is that is under investigation—perhaps the entire Occupy movement—it is not Harris’s alleged disorderly conduct. New York criminal defense attorney, Earl Ward, who is familiar with the case, but not involved in it, calls it a “fishing expedition meant to have a chilling effect on protest” and says it is “prosecutorial abuse, an effort by the DA’s office to get into personal communications of these protesters, for the purpose of chilling their First Amendment rights.”

Communication via social networks, along with texting, is how many Occupiers, like much of the world, talk to one another. Tapping phones may be passé, but the dangers of more modern electronic “eavesdropping” are not.

At a recent Manhattan gathering of Occupy supporters, Bernadine Dohrn, who with her husband, Bill Ayers, has been traveling around the country visiting different Occupy sites, rightly warned the audience that the latest communication technology “is a weapon in the hands of Occupiers, and is also a weapon in the hands of the State.”

Opposition papers have not yet been filed with the clerk of the Criminal Court. The assistant DA assigned to the case declined to discuss it or answer any questions, as did a spokeswoman for the office.