[5] On October 28, 2013, Senator Dianne Feinstein, long described as a staunch defender of the National Security Agency (NSA), announced that a "total review of all intelligence programs is necessary".

"[13][14] Feinstein defended data collection in her press release, saying that "The threats we face—from terrorism, proliferation and cyber attack, among others—are real, and they will continue.

While noting that the committee had encountered inadvertent violations of the law, the majority reported "It remains the case that, through seven years of oversight of this metadata program under Section 215, the Committee has not identified a single case in which a government official engaged in a willful effort to circumvent or violate Section 215 in the conduct of the bulk telephone metadata program."

[18][19][20] The ACLU and EFF were among fifty-four "civil liberties and public interest groups" that authored a coalition letter to Congressional leadership urging them to oppose the act.

[21] One area of concern raised by The Guardian, crediting blogger Marcy Wheeler, regards a "backdoor search provision" which could allow domestic U.S. law enforcement agencies warrantless access to the data.

A FISA court document declassified in 2011[22] and a leak by Edward Snowden previously published by the newspaper[23] indicated that generally searches of the database for "U. S. Persons" was not permitted, but contained a provision that: According to The Guardian, Section 6 of the Act "blesses" such a procedure, permitting intelligence agencies to search "the contents of communications" collected overseas for U.S. persons provided that the purpose pertained to "foreign intelligence information".

[24] The provision was also criticized by Senator Ron Wyden, who said that the bill "would give intelligence agencies wide latitude to conduct warrantless searches for American phone calls and emails", instead supporting the USA Freedom Act by Senators Patrick Leahy and F. James Sensenbrenner that would require a search warrant to obtain the information.