A White House panel examining the privacy and legal fallout from the massive National Security Agency spying revealed by whistleblower Edward Snowden concluded that the snooping was lawful yet "close to the line of constitutional reasonableness."

The Privacy and Civil Liberties Board said that the programs that tap undersea cables and acquire data from ISPs like Yahoo and Google with broad orders from a secret court are "authorized by Congress, reasonable under the Fourth Amendment, and an extremely valuable and effective intelligence tool."

The 191-page report (PDF), released late Tuesday, was largely condemned by civil liberties advocates and scholars.

"Sadly, the board has failed to fulfill its responsibility here, which is to ensure that counterterrorism policies safeguard privacy and civil liberties,” Elizabeth Goitein, a director of the Liberty and National Security Program at the Brennan Center for Justice. “The collection of Americans’ phone calls and e-mails without a warrant is unconstitutional, regardless of whether they are communicating with their next-door neighbor or a suspected terrorist overseas. The board, however, endorsed a ‘foreign intelligence exception’ to the Fourth Amendment’s warrant requirement that is far broader than what any regular federal court has ever recognized. The board's recommendations would leave in place the government’s ability to spy on its citizens—along with their friends, family members, and business partners overseas—without any suspicion of wrongdoing.”

Jameel Jaffer, the American Civil Liberties Union's deputy legal director, agreed. "This is a weak report that fails to fully grasp the civil liberties and human rights implications of permitting the government sweeping access to the communications of innocent people," he said.

The data being scooped up is supposed to target foreigners suspected of terrorism. Section 702 of the FISA Amendments Act grants the NSA the power to target "non-US persons reasonably believed to be located abroad." Yet individual warrants are not required, even if the snooping is performed on US soil.

Further, Americans' communications are often scooped up in the process, and the authorities sometimes perform so-called "backdoor" searches into that data as well with search terms like a US phone number or e-mail addresses of known Americans.

The board said the US could continue to spy on Americans without individual warrants if the authorities believe the results would "likely" produce foreign intelligence. If it does not, the data should be deleted, the board recommended.

Earlier this year, the privacy board concluded that the NSA's bulk telephone metadata program was a Fourth Amendment breach and did little to combat terrorism. That surveillance program remains largely intact.

None of the report is binding on President Barack Obama or Congress.