As Democrats and Republicans debate legislation that would alter 30-year-old limits on intrusive electronic and physical searches by the government, the secretive 11-member court that oversees surveillance of foreign-intelligence targets in the United States finds itself in the middle of a very public power struggle.

Regardless of where law and policy makers fall on the question, now being debated, about which governmental branch should hold the most sway over intelligence operations, and which political party has the more effective and fair solution, they all agree on this much: The Foreign Intelligence Surveillance Court should play referee, and the government should receive some kind of authorization for a still-secret set of spying activities that many agree are essential to the war on terrorism. If that oversight results in warrants that violate the Constitution, as some scholars fear would occur if pending legislation is enacted, most Republicans and Democrats don’t appear concerned about such a prospect or even cognizant of it. Such is the court’s brave new world.

It is an odd, but perhaps not unwelcome, reality that the intelligence judges now play a decisive role in this controversy. Odd because for most of American history, the judiciary has ruled itself least qualified among the branches of government to manage intelligence activities. But not unwelcome because this court has waded into these waters before, and it believes it has been an indispensable buffer against government excess.

The 1978 Foreign Intelligence Surveillance Act, the court’s animating law, was a grand political compromise. After years of unchecked surveillance by the FBI and intelligence agencies of prominent Americans and political dissidents both before and during the Nixon presidency, the FISA court became the arbiter of when and how the executive branch can spy on suspected foreign agents and terrorists inside the country. Especially after the 9/11 attacks, the judges have included more experts in national security law, court-watchers say, and the court’s former chief judge has proudly proclaimed that the court turns down almost no surveillance requests because the government has learned to play within FISA’s boundaries.

This system, however, was upended after the 9/11 attacks, when President Bush issued orders that allowed him to bypass the court when tracking domestic terrorism suspects. The orders seemed to reflect a long-held, simmering animosity toward the body by some senior administration officials, particularly Vice President Cheney’s legal counsel, David Addington, who reportedly told a colleague after 9/11 that “we’re one bomb away from getting rid of that obnoxious court.”

Now, though, the court is regaining some of the authority it had lost. And if the president signs a new Democratic proposal to further amend FISA, the court would play a central and untested role in overseeing surveillance. It may welcome the chance.

Former Chief FISA Court Judge Royce Lamberth has described a panel of jurists confident in its interpretation of surveillance law, equipped to issue warrants quickly, and flexible enough to write new procedures during wartime. In remarks at the annual conference of the American Library Association in June, Lamberth, who left his post in 2002, said he hadn’t found a better way of controlling government surveillance. But, the former judge added, there was a “worse way,” and that was “what the president did with the National Security Agency”: Bush’s post-9/11 orders allowed the government’s eavesdroppers to intercept communications inside the United States without the court’s approval.

The NSA program, begun just after 9/11 and dubbed “the terrorist surveillance program” by Bush, continued without judicial check for more than five years, until January 2007, when the administration placed it under FISA court review. The exact contours of the court’s initial orders about the program, which were to last for 90 days, are secret.

For that first 90-day period, the NSA program proceeded unimpeded, intelligence officials say. But, according to Mike McConnell, the director of national intelligence, in spring 2007 a different FISA judge said that the government needed a warrant to capture electronic communications between parties in foreign countries as those communications pass through routing equipment in the United States. “We found ourselves in a position of actually losing ground,” McConnell told the El Paso Times in August. The government would have to apply for a warrant for each phone number it monitored in this way, and it takes about “200 man-hours” to fill out the necessary paperwork, McConnell said. FISA experts and lawmakers note, however, that the law contains emergency provisions that allow monitoring to begin before a court order.

The ruling on the U.S.-routed calls was a rare push-back from a court that, by Lamberth’s count, has approved 99 percent of the government’s warrant applications. The Bush administration then launched a massive lobbying effort to amend FISA; in August, Congress passed the Protect America Act. It effectively reversed the court’s normal procedures (these require a warrant before surveillance) and gave judges an after-the-fact-review power for surveillance procedures, which inevitably pick up domestic communications when foreign targets call or e-mail people located in this country. The law was panned for its hasty and imprecise language, and some observers thought it even authorized warrantless physical searches of people’s possessions and premises.

This brings the court to its current crossroads. To correct the law’s deficiencies, as they see them, Democratic Reps. Silvestre Reyes of Texas and John Conyers of Michigan, the respective chairmen of the House Intelligence and Judiciary committees, have introduced the RESTORE Act, short for Responsible Surveillance That is Overseen, Reviewed, and Effective. The Democrats have said that the bill would “protect innocent Americans from warrantless eavesdropping.” Republicans have blasted it as a roadblock in the executive’s path, and the bill was suddenly pulled from the House floor on October 17. But as Benjamin Wittes, a Brookings Institution scholar and an expert on the FISA court, writes in The New Republic Online this week, Protect America and RESTORE are actually quite similar. They do, however, hold significant implications for the court.

“Under either approach, the [NSA] will have the legal authority to listen to your calls without first going to the [FISA] court to get a warrant,” as long as the targets are people overseas calling people in the United States, Wittes writes. Under the Protect America Act, which the administration favors, the FISA court plays “only a tiny retroactive role in approving procedures for overseas surveillance.” But under RESTORE, the court “would play a slightly-less-tiny role in rubber-stamping [surveillance] programs,” Wittes maintains. The court, under RESTORE, is given additional powers to review and modify “minimization procedures,” which are secret, are written by the government, and are supposed to ensure that information about “U.S. persons” (defined as U.S. citizens or legal residents) is scrubbed from intelligence reports.

Under the RESTORE Act, the court would also have a new, controversial power: granting programmatic or “blanket” warrants for whole classes of individuals overseas who are not U.S. persons. Historically, courts have ruled that such orders violate the Fourth Amendment, which requires that warrants be issued against specific individuals and locations. And although the foreign targets of surveillance don’t enjoy constitutional protections, the U.S. persons whom they might call do.

Wittes argues that the RESTORE Act’s “approach is a little like asking the courts to approve the reasonableness of police arrest policies prospectively instead of reviewing individual arrests. It’s not the way we traditionally do things in the American constitutional system — and it creates a potentially serious set of constitutional problems with the bill.” But the law would require the administration to submit to the court “the procedures it uses to determine which surveillance is exempt from FISA — and the court has the ability to send them back if they’re unreasonable,” he adds.

Under the previous version of FISA, the judges found ways to discipline the government. They could reject an application for a warrant; in one case, Lamberth barred a senior FBI official from appearing before the court, because he said that the official had presented false information. The RESTORE Act wouldn’t really take these powers away.

Still, some see the recent amendments to FISA as a further weakening of constitutional protections. “There are significant problems that existed with FISA before the Protect America Act,” says Jameel Jaffer, the director of the American Civil Liberties Union’s National Security Project, who is leading a legal effort to have the court release its written opinions on the NSA’s surveillance program.

The court “was created to circumvent the Fourth Amendment,” says Jonathan Turley, a professor at the George Washington University Law School and one of the few lawyers ever to go inside the court’s secure room. With the Protect America and RESTORE acts, Turley says, “Democrats and Republicans are amending the Constitution by default.”

For their part, the FISA court judges are unlikely to weigh in directly on the constitutional debate. But using history as a guide, it seems unlikely that they’ll do anything more or less than apply the statute as directed by Congress. Presumably, they’ll also steer clear of deciding how valid the statute actually is.