There is more bad news this week for the National Security Agency (NSA) cell phone spying program when an independent panel appointed to evaluate the issue found, in a divided opinion, that the program is illegal under federal law. Three of the five members of the Privacy and Civil Liberties Oversight Board (PCLOB) found that the U.S. Patriot Act, under which the NSA was said to be operating the program, did not allow for the warrantless collection of metadata from Americans’ cell phone activities, and has not demonstrated significant benefits in preventing terrorist attacks.

“We have not identified a single instance involving a threat to the United States in which the telephone records program made a concrete difference in the outcome of a counterterrorism investigation,” read the report, a copy of which was obtained by The Washington Post. “Moreover, we are aware of no instance in which the program directly contributed to the discovery of a previously unknown terrorist plot or the disruption of a terrorist attack.”

The conclusion of the panel is important, as federal judges evaluating the NSA program have handed down conflicting opinions on the legality of the activities. While President Obama has promised changes to the program in recent days, he did not call for an outright stop to the practice. The Post reports that the panel briefed the White House on its opinion before it goes public.

Despite the program’s support by the U.S. Justice Department and several federal surveillance judges, the panel found that Section 215 of the Patriot Act, which supposedly gives the NSA the right to conduct the broad spectrum surveillance, does not authorize the spying. That statute requires that records sought by the government — in this case phone numbers dialed, call times and durations, but not call content — be relevant to an authorized investigation, according to the Washington Post.

This is the second blow to the NSA’s phone surveillance program this week. At the World Economic Forum at Davos, European officials announced the formation of a major independent commission that will investigate the NSA program alongside modern Internet technologies’ future effects on privacy, censorship and surveillance. Intelligence leaked by Edward Snowden, a former employee of CIA contractor Booz Allen Hamilton revealed that the NSA program was even gathering data from the cell phones of world leaders, including that of German Chancellor Angela Merkel. The 25 member panel will be headed by Swedish foreign minister Carl Bildt.

Shortly after the Privacy and Civil Liberties Oversight Board (PCLOB)’s opinion was released, the Obama Administration disputed the findings and indicated that it would not be taking the opinion under advisement. Given the conflicting legal opinions, it seems likely that the issue will ultimately reach the U.S. Supreme Court.