The federal government’s ability to keep a massive database on Americans’ phone records is set to get further scrutiny as the American Civil Liberties Union on Friday asked an appeals court to review a recent decision that found the database to be lawful.

According to the ACLU, US District Judge William Pauley III erred in a December 27 ruling when he concluded that the NSA’s collection of telephony metadata — a comprehensive record of phone number activity supplied by Verizon(s vz) and phone carriers — does not amount to an illegal search under the Constitution.

Pauley III repeatedly invoked the specter of terrorist attacks and the government’s need to “connect dots” to say the program is lawful, and throw out the ACLU’s complaint. The judge’s position upset civil libertarians.

“The government has a legitimate interest in tracking the associations of suspected terrorists, but tracking those associations does not require the government…