WASHINGTON -- It meets for a few days each month in a windowless room in the Justice Department basement, a highly secretive court that can shape how the government spies on some U.S. residents.
Already viewed warily by civil libertarians, the court will grow more powerful because of the tougher anti-terrorism laws President Bush signed into law last month.
The court considers requests, almost always from the FBI, for warrants and searches related to foreign intelligence operations inside the United States. From what little is known of the operation, the warrants typically allow the government to listen in on suspected spies or terrorists.
Civil liberties and privacy watchdogs say the court established by the Foreign Intelligence Surveillance Act now will be free to approve more and broader wiretapping against a wider range of people. The government may never have to disclose who was targeted, or why.
"FISA already had just the minimal trappings of a judicial process," said David Sobel, a lawyer with the Electronic Privacy Information Center. The anti-terrorism measures "chip away at the very minimal procedures that currently exist."
The court has approved thousands of warrants since it was established by Congress in 1978, and only once has turned down the government.
There is a good reason for the strong government track record, said former Attorney General Richard Thornburgh.
"They're so meticulously prepared," he said.
The court was intended to police the kind of surveillance abuse seen in the Nixon era, by requiring the FBI to go before a judge to get a national security-related warrant. Previously, the Justice Department or the White House could order such surveillance directly.
"It acts as a brake on people acting imprudently," Thornburgh said. "I am quite sanguine that it will continue to play that role."
Civil libertarians have always been uneasy with the law and the court, because FISA allows the government to do things in the name of national security that would be illegal or unconstitutional if done as part of a regular criminal investigation.
Under FISA, domestic surveillance can begin once the government shows a suspect is probably a "foreign power or agent of a foreign power."
Law enforcement must meet a higher standard -- probable cause that a crime was committed -- to get an ordinary criminal warrant.
The different standards were permitted because secret FISA surveillance is supposed to help protect the country, rather than gather information about a particular person that could be used against them in court.
The new anti-terror laws effectively eliminate that distinction, said Kate Martin, director of the Center for National Security Studies.