Last month the San Francisco District Attorney’s office went on a fishing expedition. After EFF and ACLU got involved, the DA wisely cut bait.

The fishing expedition cut short by the DA last week consisted of a pair of subpoenas issued to Twitter, seeking tweets, photos, and a trove of other information related to the accounts of two activists, Robert Donohoe and Lauren Smith, whom the SF DA has charged with a number of offenses stemming from a Columbus Day anti-capitalist protest. After Twitter notified the users, attorneys for Donohoe and Smith opposed the subpoenas, and ACLU and EFF supported their efforts.

Not only did the subpoenas to Twitter violate federal law (the Stored Communications Act makes clear that the government cannot use a subpoena to gain access to the content of communications), but they violated the First and Fourteenth Amendments to the Constitution as well. Government surveillance of what we say—even in public—has a chilling effect on speech. That is why courts have held that any effort to compel the disclosure of a person’s communications or associations must be narrowly tailored.

The subpoenas issued in this case were anything but narrow. Not only did the requests seek Donohoe and Smith’s own tweets, but also all communications by any Twitter user (presumably including both tweets and private Direct Messages) that even mentioned them. Further damning the DA’s subpoenas was the wildly overbroad ten-month time period they covered. As we wrote in our brief to the court, a “district attorney’s decision to prosecute is not an invitation for the government to engage in intrusive fishing expeditions into a criminal defendant’s opinions, beliefs, and interests, let alone the opinions, beliefs, or interests of third parties unconnected to the charged crime other than that they have once uttered the names of defendants or their Twitter accounts.”

While we appreciate the San Francisco District Attorney’s decision to withdraw these unconstitutional subpoenas, we are deeply concerned that they were issued in the first place. It seems that throughout the country, law enforcement is subpoenaing this information almost routinely in connection with criminal investigations. Last year, EFF and ACLU supported Twitter’s ultimately unsuccessful fight against New York City prosecutors attempt to get account information and tweets about an Occupy Wall Street protestor with a subpoena. And Google’s semi-annual Transparency Report has shown growing law enforcement requests for user data.

Going forward, we urge the San Francisco District Attorney, and prosecutors around the country, not to engage in these sorts of unconstitutional, speech-chilling, fishing expeditions. Requests for data from companies like Twitter should be narrowly focused on as small of a time frame and as few people as possible. Finally law enforcement may not use subpoenas to access content but must instead rely on search warrants, which require probable cause and come with greater judicial supervision.