Icelandic parliament member Birgitta Jónsdóttir, computer security researcher Jacob Appelbaum and Dutch activist Rop Gonggrijp had filed a request blocking the subpoena while the case was considered by a federal appeals court. O'Grady denied the motion, saying their appeal had little chance of success based on existing U.S. case law.
"Litigation of these issues has already denied the government lawful access to potential evidence for more than a year," O'Grady said in his ruling. "The public interest therefore weighs strongly against further delay."
We've asked Twitter for comment on the ruling. We'll update as soon as we hear back. Twitter's guidelines for law enforcement say the company notifies users when information is requested unless forbidden from doing so by statute or court order.
The three Wikileaks supporters had argued the subpoena, which seeks private messages and other information, violates their privacy and rights established under the First Amendment.
"We're obviously disappointed by this ruling and we think the judge got it wrong," Aden Fine, a lawyer with the American Civil Liberties Union who represents Jónsdóttir, told Bloomberg Businessweek.
The data is being sought as part of the federal government's ongoing criminal investigation into WikiLeaks founder Julian Assange. The government is looking at possible criminal charges against Assange and others who leaked diplomatic cables and classified military documents through the WikiLeaks website.