In the fall of 2002, as Congress debated waging war in Iraq, copies of a 92-page assessment of Iraq's alleged weapons of mass destruction sat in two vaults on Capitol Hill, each protected by armed security guards and available to any member who showed up in person, without staff.

But only a few ever did. No more than six senators and a handful of House members read beyond the five-page National Intelligence Estimate executive summary, according to several congressional aides responsible for safeguarding the classified material.

The lack of congressional attention to the nitty-gritty details of Iraq's weapons programs is symptomatic of Congress's approach to a range of intelligence matters, according to current and former intelligence committee members and a broad swath of intelligence experts.

Responsibility for congressional oversight is vested in the House and Senate select committees on intelligence, which get daily classified reports from the intelligence agencies and annually review and approve the intelligence budget. But as described by former members and outside experts, the committees' performance in oversight and investigations has deteriorated.

"The oversight is still by and large feckless and episodic," said Loch Johnson, a University of Georgia professor who has written extensively on the subject. "September 11 was an intelligence failure, but it's also a policy failure, not only in the White House but in Congress. There's really a heavy onus on these intelligence committees to probe what's going on."

The committees' role in oversight and investigations "has almost gone away," said former representative Timothy J. Roemer (D-Ind.), a committee member for three years and now a member of the independent commission investigating the Sept. 11, 2001, attacks. "You're so busy with the budget and keeping up with daily events."

Iraq is not the only major issue on which experts say the intelligence committees fumbled: The CIA, the FBI and the Bush administration have come under sharp criticism recently for not detecting and disrupting al Qaeda's plot against the United States. But for the past 10 years, the intelligence agencies shared considerable classified information about the growing capabilities of al Qaeda, and committee members did little to ring an alarm.

The chairmen and vice chairmen of the committees, for example, had seen and discussed five major "memorandums of notification" describing presidentially directed covert actions against al Qaeda and Osama bin Laden, according to recent testimony by CIA Director George J. Tenet. Tenet also listed bin Laden as one of the top three threats facing the United States each year since he became the director in 1997, and in classified session the agency described the threat in detail.

Had they demanded to know, the committees would have discovered that before Sept. 11, 2001, the FBI had no real idea of al Qaeda's strength within the United States, according to Sen. Bob Graham (D-Fla.) and the joint House-Senate report on the Sept. 11 attacks.

"The committee could have and should have given more attention to the emerging threat [of terrorism] and assessed how well our intelligence community was making the transition from the Cold War into the new era," said Graham, who was chairman of the Senate intelligence committee when the attacks occurred.

Committee members acknowledge in hindsight that they presided over damaging cuts in the CIA's operational budget over the past decade. They knew the details: that the intelligence community's budget had been cut every year between 1990 and 1996, and that it remained flat from 1996 to 2000. They knew the agency had been forced to cut 25 percent of its personnel and closed some stations overseas.

As Tenet told the Sept. 11 panel on April 14, "The infrastructure to recruit, train and sustain officers for our clandestine services -- the nation's human intelligence capability -- was in disarray." And, he added, "we were not hiring new analysts, emphasizing the importance of expertise or giving analysts the tools they needed."

There are other examples of Congress's lack of interest in the details of intelligence:

* Although many have criticized the president for appearing inattentive to reports on al Qaeda before Sept. 11, the Senate intelligence committee, which is given classified daily reports on terrorism and other intelligence, held only one closed-door hearing devoted to al Qaeda and bin Laden in the months before the attacks, according to congressional and administration officials. Some staff members recalled holding a second meeting; others did not.

* Forty-six senators -- none of them members of the intelligence committee -- demanded that the CIA declassify a section of the House-Senate Sept. 11 report that dealt with Saudi Arabia, saying it was crucial to the public's understanding of the terror plot. But most of the 46 senators, including the campaign's leader, Sen. Charles E. Schumer (D-N.Y.), never read the 28 pages they insisted be released. "I intentionally didn't read it because this administration plays hardball on things like this," said Schumer, who said he talked to senators who had read the 28 pages and told him it contained no real secrets. "Had I read the report and been critical, they would have accused me of leaking it the way they've done with other senators."

* The House intelligence committee believed the voluminous House-Senate report was so important that it temporarily changed its rules to allow all members of the House to read the classified report. "There weren't a lot of takers on the 9/11 report," said Rep. Jane Harman (D-Calif.), the committee's vice chairman. Partly, she said, this was because members' personal staffs were not given access, leaving the hard work to members themselves. "Some didn't want to do the homework," she said.

Sen. John D. Rockefeller IV (D-W.Va.) said some members with packed daily schedules are deterred simply by the prospect of trekking across Capitol grounds to the secure Hart Senate Office Building room where the Senate's classified material is kept.

"Everyone in the world wants to come to see you" in your office, he said, and having to go to the secure room is "not easy to do." Members can't take notes, there is no staff to synthesize the material, and "it's extremely dense reading," he said. "It's the Brahms of music."

The congressional intelligence panels are unusual among Capitol Hill committees. Members do not have committee staffers assigned to them, for example, so greater responsibility for oversight resides with the members, and with the committees' overworked professional staffs.

House and Senate traditions and rules also mean the panels work without the typical scrutiny by the public or interest groups. Both committees rarely hold public hearings. The business they conduct behind closed doors, even when it is not classified, cannot be discussed publicly without committee approval. Staff members have been fired for sharing information about unclassified matters with staff members of other committees.

Also, rules established after the 1975 hearings chaired by Sen. Frank Church (D-Idaho) that exposed CIA abuses overseas give unusual powers to the committees' chairmen and vice chairmen. They alone are briefed on the most sensitive covert actions, for example. To prevent members from being co-opted by the intelligence community, the commission also set eight-year term limits.

But the term limits, members and outside experts say, have significantly hobbled members' ability to develop a firm understanding of the secret world they enter, one in which even the basic acronyms are unfamiliar.

"The learning curve on this committee is the toughest of any committee I've served on," said Sen. Mike DeWine (R-Ohio), a committee member who favors lifting the term limits. "It's really technical, really tough."

Making the learning curve even steeper, DeWine said, is a culture of passive resistance within intelligence agencies. "They answer your questions, but you have to ask the right questions. What counts on the committee is experience and institutional memory," he said.

But experience levels on intelligence committees pale in comparison to the panels' closest counterparts, the armed services committees. Sen. John W. Warner (R-Va.), the former Navy secretary who is chairman of the Senate Armed Services Committee, has been the committee's chairman or ranking member a total of nine years and has served on the committee for 26 years. Sen. Pat Roberts (R-Kan.), who spent most of his career on Capitol Hill, has chaired the intelligence panel for one year and is in his eighth and last year on the committee.

Sen. Carl M. Levin (D-Mich.), a lawyer and vice chairman of the Armed Services Committee, has spent 25 years on that panel, the last seven as chairman or vice chairman. By contrast, Rockefeller, a former college president and Peace Corps volunteer, joined the intelligence committee 31/2 years ago and became its vice chairman 15 months ago.

"The way the intelligence business has expanded, given what we are confronted with, I'm sorry to say, but the days of a handful of people" overseeing intelligence "are gone," said Rep. Porter J. Goss (R-Fla.), chairman of the House intelligence committee and a former CIA case officer.

Goss and most other members of both committees say the term limits should be abolished, at least for some members. DeWine and others say the committees need major reworking.

"There is a general consensus among most of us," DeWine said, that "we need to restructure the intelligence committee. There's a realization of how difficult it is to really understand what's going on in the intelligence community."

Restructuring will not ease the partisanship that has recently dominated both committees as they try to wrap up nine-month reviews of the intelligence community's faulty prewar assessment that Iraq possessed weapons of mass destruction.

When Democratic senators demanded that the committee also scrutinize how the Bush administration publicly portrayed intelligence, the committee came up with a compromise: a second report devoted to that topic, to be published before the end of the year. At the moment, however, finishing the first report has been bogged down by party-line squabbling over how far to go in criticizing the CIA.

Meanwhile, Republicans and Democrats on the House committee have gone their separate ways entirely, with the minority and majority each working on its own report.

Roberts, chairman of the Senate committee, said the partisan finger-pointing diverts attention from solving the systemic problems facing the intelligence community.

"We're in danger now of seeing the politicization of the whole intelligence issue," Roberts said. "What really worries me is this 'gotcha' business."

Sen. Mike DeWine said the panel's learning curve is steep. Sen. Charles E. Schumer cited a fear of leak accusations.