News that the National Security Agency has overstepped its legal authority thousands of times in recent years is ratcheting up pressure on President Obama to accept reforms to the surveillance programs.
Last Friday, Obama tried to quell the growing uproar over NSA spying by laying out a series of steps to increase transparency and toughen privacy protections. He insisted the programs are critical to national security, but he acknowledged that certain changes might be necessary to restore the public's confidence.
The news also raises the stakes for the White House's decision about whom to appoint to an NSA review board. Obama promised the review group would be made up of independent experts. If he chooses only longtime intelligence officials, he is likely to spark further outrage from privacy advocates.
On Thursday, The Washington Post published an internal NSA audit, leaked by Edward Snowden, showing that the agency obtained private communications thousands of times in recent years without proper authorization.
The incidents were mostly unintended and typically involved unauthorized surveillance of Americans or foreign targets in the United States, the paper said.
They were often the result of typographical errors, but the more serious violations included unauthorized access to intercepted communications and use of automated systems that did not have privacy safeguards built into them.
In one incident, the NSA intercepted a "large number" of calls from Washington because of a programming error that confused the capital’s 202 area code for 20, the international code for Egypt.
According to The Post, the NSA did not always reveal the violations to the Foreign Intelligence Surveillance Act (FISA) court, which is supposed to oversee the secret surveillance and enforce legal protections.
"NSA's foreign intelligence collection activities are continually audited and overseen internally and externally," an NSA spokesman said in a statement. "When we make a mistake in carrying out our foreign intelligence mission, we report the issue internally and to federal overseers and aggressively get to the bottom of it."
White House spokesman Josh Earnest insisted: “This administration is committed to ensuring that privacy protections are carefully adhered to, and to continually reviewing ways to effectively enhance privacy procedures.”
Meanwhile, Senate Judiciary Committee Chairman Patrick Leahy (D-Vt.) said he will hold another hearing to examine the surveillance programs. He also questioned whether intelligence officials have been fully honest with Congress.
"The American people rely on the intelligence community to provide forthright and complete information so that Congress and the courts can properly conduct oversight. I remain concerned that we are still not getting straightforward answers from the NSA," Leahy said in a statement.
House Democratic Leader Nancy Pelosi (Calif.), who has defended aspects of the surveillance and voted against curbing the phone data collection program last month, called the latest report "extremely disturbing."
"Congress must conduct rigorous oversight to ensure that all incidents of non-compliance are reported to the oversight committees and the FISA court in a timely and comprehensive manner, and that appropriate steps are taken to ensure violations are not repeated,” she said in the statement.
In a joint statement, Sens. Ron Wyden (D-Ore.) and Mark Udall (D-Colo.), fierce critics of the surveillance programs and members of the Intelligence Committee, said the latest revelation is "just the tip of a larger iceberg."
They argued that the public should know more about violations of secret court orders and that the FISA court should be given new powers to oversee the NSA. They reiterated their support for establishing a public advocate who would push for privacy rights before the FISA court, a proposal backed by President Obama.
Even Sen. Dianne Feinstein (D-Calif.), the chairwoman of the Senate Intelligence Committee and a vocal defender of the NSA, endorsed tougher oversight of the agency.
"The [intelligence] committee can and should do more to independently verify that NSA’s operations are appropriate, and its reports of compliance incidents are accurate," she said.
Feinstein told The Washington Post that she had not seen a copy of the audit until the paper showed it to her. But in a statement, her office clarified that she has received "FISA compliance information in a more official format." It is unclear whether she had been fully briefed on all of the information in the leaked audit.
Feinstein emphasized that most of the incidents were unintentional and said she is unaware of any occasion on which the NSA has "abused its authority to conduct surveillance for inappropriate purposes."
House Intelligence Committee Chairman Mike Rogers (R-Mich.) offered a full-throated defense of the surveillance programs.
He claimed the documents show there was "no intentional and willful violation of the law," and he emphasized that Congress and the courts have already put "in place auditing, reporting, and compliance requirements."
"Human and technical errors, like all of the errors reported in this story, are unfortunately inevitable in any organization and especially in a highly technical and complicated system like NSA," Rogers said.
But Michelle Richardson, a legislative counsel for the American Civil Liberties Union (ACLU), said in an interview that the documents show systemic compliance problems at the NSA.
"It's more evidence that secret oversight and secret courts and secret laws don't work," she said.
She predicted that there would be "bicameral, bipartisan support for aggressively rewriting the disclosure requirements."
Richardson said it would be easier for Congress to enhance oversight of the NSA than to dramatically curb its surveillance powers.
"These are the sorts of changes that Congress likes to do because they're not actually making policy decisions," she said.
—Jeremy Herb and Jennifer Martinez contributed