By Brendan Sasso - 05/08/12 06:55 PM EDT
"If the Fourth Amendment’s warrant requirement applies merely to surveillance of one’s location in public areas for 28 days, it also applies to the District Attorney’s effort to force Twitter to produce over three months worth of a citizen’s substantive communications, regardless of whether the government alleges those communications are public or private," Twitter wrote.
The company also argued that Harris has a legal right to challenge the subpoena on his own.
Prosecutors had argued that Harris lacked the legal standing to protect his tweets, but Twitter argued that its terms of service give its users control over their own communications.
The company said it would be an "overwhelming burden" to try to examine the merits of all law enforcement subpoenas on its own.
The American Civil Liberties Union (ACLU) praised Twitter in a blog post.
"This is a big deal," wrote ACLU senior attorney Aden Fine. He said police are becoming "increasingly aggressive" in attempts to obtain information on people's Internet activity.
"If Internet users cannot protect their own constitutional rights, the only hope is that Internet companies do so," he wrote.
Twitter's communications team, using the account @twittercomms, tweeted a link to the ACLU post and wrote, "It's not every day the @ACLU says something's a 'big deal' — Twitter Stands Up For One Of Its Users." The group added the hashtag, "corevalues."