On October 1, 2011, over 700 Occupy Wall Street protesters were arrested on the Brooklyn Bridge. Most of the protesters, including Malcolm Harris, were charged with the mundane crime of disorderly conduct, a "violation" under New York law that has a maximum punishment of 15 days in jail or a $250 fine.

And yet on the basis of a charge no more consequential than speeding ticket, the New York City District Attorney's office sent a poorly worded subpoena to Twitter requesting "any and all user information, including email address, as well as any and all tweets posted for the period of 9/15/2011-12/31/2011" regarding Mr. Harris' Twitter account, @destructuremal. Unsurprisingly, the government wanted to keep it quiet, but thankfully Twitter didn't listen. Instead, as it has consistently warned law enforcement, Twitter notified Mr. Harris, who through his lawyer, Martin Stolar of the National Lawyers Guild, has moved to challenge the subpoena in court.

The subpoena is astonishing not only for its poor grammar, but also for the breadth of information the government wants for a trivial crime that hardly requires it. The government's request that Twitter hand over Tweets is unlikely to succeed because consistent with the Stored Communications Act, Twitter releases "contents of communication" (effectively Tweets and private messages between Twitter users) only with a search warrant. In any event, Mr. Harris' account is "public", meaning the government could obtain Tweets simply by checking out Mr. Harris' Twitter feed. Plus, requesting Tweets only highlights the absurdity of the entire situation: why would the government need Tweets from both before and after the October 1 protest to prove he was obstructing traffic on the bridge? Government fishing expeditions like this raise serious First Amendment concerns. Mr. Harris was very outspoken about his support of and involvement in the Occupy Wall Street movement. With this overbroad subpoena, the government would be able to learn about who Mr. Harris was communicating with for an extensive period of time not only through Tweets, but through direct messages. And with the government's request for all email addresses associated with @destructuremal, they could subpoena Mr. Harris' email provider to get even more information about who he communicated with. The First Amendment shouldn't be trampled with only an expansive subpoena in a case that barely registers as "criminal."

Given that much of Mr. Harris' Twitter information (like Tweets and followers) is already public, it's very likely that the government was really after something else: location data. By attempting to subpoena these records, the government can get around the Fourth Amendment's prohibition against warrantless searches by requesting information that includes IP addresses. Twitter keeps track of IP address information regarding every time a person logged into Twitter, as well as the IP address information related to a Twitter user's direct messages to other users, and the date and time information related to these log ins and direct messages. Armed with IP addresses, the government -- without a warrant -- can go to an ISP to determine who was assigned that particular IP address. And if that person connected on a mobile device -- which is where the majority of Twitter users access their accounts -- the ISP will hand over to the government the specific cell tower (and its corresponding geographic location) which that person used to access Twitter. This allows the government to piece together a map of where a person physically is when he opens Twitter on his smartphone, sends a direct message to a friend, or Tweets. And with that information, the government could get a record of Mr. Harris' movement over the three months it requested from Twitter. It's no surprise then that the government singled out Mr. Harris for this request: he currently has over 1,500 followers and 7,200 Tweets.

Allowing the government to gets its hands on this data with nothing more than an administrative subpoena renders the Fourth Amendment meaningless. Only with the protection of a search warrant, and the heightened judicial supervision that comes along with it, can the voracious appetite of law enforcement be curbed. As we've consistently argued, the Fourth Amendment protects this information. But another way to impose privacy protection from the prying hands of law enforcement is through Congressional reform of the badly outdated Electronic Communications Privacy Act ("ECPA"). As part of the Digital Due Process coalition, EFF has been calling for Congress to update ECPA to conform with the realities of the 21st century.

It looks like judicial momentum may finally be on our side. In January of this year, the United States Supreme Court issued a landmark decision in United States v. Jones (PDF), ruling that law enforcement could not physically install a GPS device on private property without a search warrant. The majority opinion resolved the Fourth Amendment issue by looking exclusively at the physical installation of the GPS device. Importantly, however, in a concurring opinion, Justice Sotomayor warned that "physical intrusion is now unnecessary to many forms of surveillance." Collecting IP addresses of a prolific Tweeter, and matching it with other easily obtainable information from other service providers, demonstrates this problem. In writing that society is unlikely to accept extensive warrantless surveillance as "reasonable", Justice Sotomayor called into question "the appropriateness of entrusting to the Executive, in the absence of any oversight from a coordinate branch, a tool so amenable to misuse, especially in light of the Fourth Amendment’s goal to curb arbitrary exercises of police power to and prevent 'a too permeating police surveillance.'” Similarly, Justice Alito's concurring opinion noted that with "dramatic technological change, the best solution to privacy concerns may be legislative."

Hopefully with the public breathing down its neck, Congress can finally act to fix a antequated set of laws. Malcolm Harris, like Birgitta Jonsdottir before him, took a stand to protect our privacy rights. You can too by telling Congress that its time to update ECPA and tell law enforcement once and for all that in order to get a person's location data, it needs to come back with a warrant.