WASHINGTON — A special court that has routinely approved eavesdropping operations has put new restrictions on the ability of U.S. spy agencies to intercept e-mails and telephone calls of suspected terrorists overseas, U.S. officials said Wednesday.
The previously undisclosed ruling by the Foreign Intelligence Surveillance Court has prompted concern among senior intelligence officials and lawmakers that the efforts of U.S. spy agencies to track terrorism suspects might be impaired at a time when analysts have warned that the United States is under heightened risk of attack.
It also has triggered a push in Congress this week to pass temporary legislation that would protect parts of a controversial eavesdropping program launched by the Bush administration after the Sept. 11 attacks.
The administration and Democrats are at odds over how to address the issue, leading to concerns that it might not be resolved before Congress starts its August recess Monday.
This week, congressional leaders have alluded to the recent decision by the court, which was created in 1978 as part of the Foreign Intelligence Surveillance Act.
House Minority Leader John A. Boehner (R-Ohio) said in a television interview Tuesday evening: "There's been a ruling, over the last four or five months, that prohibits the ability of our intelligence services and our counterintelligence people from listening in to two terrorists in other parts of the world where the communication could come through the United States."
Senate Intelligence Committee Chairman John D. Rockefeller IV (D-W.Va.) said Wednesday that "recent technical developments" had convinced him that "we must take some immediate but interim step to improve collection of foreign intelligence in a manner that doesn't compromise civil liberties of U.S. citizens."
Neither Rockefeller nor Boehner would elaborate, but U.S. intelligence and congressional officials familiar with the matter said they were referring to the FISA court ruling.
Boehner's remarks suggest that the ruling imposed new restrictions on the National Security Agency's ability to intercept communications that are between people overseas but that "transit" U.S. data networks operated by Internet service providers and telecommunications companies.
But other officials said the ruling's reach was broader, affecting cases "where one end is foreign and you don't know where the other is" -- meaning warrants would be required even when it was unclear whether communications were crossing the United States or involved a person in the United States.
One official said the issue centered on a ruling in which a FISA court judge rejected a government application for a "basket warrant" -- a term that refers to court approval for surveillance activity encompassing multiple targets, rather than warrants issued on a case-by-case basis for surveillance of specific terrorism suspects.
"One FISA judge approved this, and then a second FISA judge didn't," the official said, speaking on condition of anonymity because the activities of the FISA court are classified.
The precise effect of the ruling is unclear, but a second official said that it "reduced the amount of intelligence we were collecting" on overseas terrorism suspects.
National Intelligence Director J. Michael McConnell has called attention to the issue in public testimony, telling a Senate committee May 1 that U.S. spy agencies are "actually missing a significant portion of what we should be getting" because of legal obstacles. But he has refused to identify the cause or nature of that intelligence gap.
The recent FISA court ruling was a blow to the Bush administration, which had bypassed the court when it launched the NSA program in 2001. The White House moved it back under the FISA court's supervision last year after Democrats won control of Congress and appeared poised to challenge the constitutionality of a program that monitored U.S. residents' communications without warrants.
The ruling comes at a time when U.S. intelligence agencies have warned that Al Qaeda has regrouped and is refocusing its energies on striking the U.S.
The issue has become the center of a fierce new debate on Capitol Hill over how to update the Foreign Intelligence Surveillance Act, which requires the government to get a special court's approval before monitoring communications of people in the U.S. Public records show that the court rejects few of the government's requests: In 2005, for example, it approved 2,072 applications and denied none; in 2006 it approved 2,176 and denied, in part, one.
This week, unable to agree on a broader overhaul, the Bush administration and congressional leaders have turned instead to passing temporary legislation designed to address concerns raised about the recent court ruling. Even so, they remain at odds over the FISA court's role.