It is one of Washington's most obscure, yet powerful, offices.

Staffed by only 50 men and women, the Office of Information and Regulatory Affairs is in its 25th year of overseeing the federal rulemaking bureaucracy. Next Monday, the AEI-Brookings Joint Center for Regulatory Studies will gather four OIRA administrators and others in the regulatory nexus to examine how various presidents have used that oversight function to achieve political and policy goals.

The conference, and the recent announcement by OIRA Administrator John Graham that he will be leaving early next year, provide an opportunity to review the evolution of the office, part of the Office of Management and Budget.

Most of the nine office administrators have left a stamp on OIRA's operation that reflects the regulatory philosophy of the administration in power. Some were public in their positions, while others were wizard-like, hiding behind an impenetrable curtain. All had power to shape regulatory policy that would affect business, public interest groups and, in many cases, every American. They are the Supreme Policy Wonks.

The office reviews about 600 of the 4,000 or so rules that the federal government issues each year, those with an impact of at least $100 million on the economy. It has authority to set procedures for agencies' scientific and economic assessment of rules and to change or kill proposals that don't jibe with an administration's political agenda. The administrator is the only staff member subject to Senate approval.

"It's the best job I ever had," said Sally Katzen, the administrator in the Clinton administration. "It really was a license to kibbutz in virtually anything in the regulatory world. I was once introduced as the woman who deals with everything from hot pants to chicken [expletive]." The remark was directed at her oversight of a rule requiring construction workers to cover their legs and how to regulate chicken fecal matter in the slaughtering process.

The office is said to have the creme de la creme of staff members, who always have called the administrator by first name. Its alumni have fanned out over the years into other influential top posts. James Miller III, the first administrator, went on to head the Federal Trade Commission and OMB. Christopher DeMuth, who succeeded Miller, runs AEI. And Wendy Gramm, a professional economist, became head of the Commodity Futures Trading Commission.

OIRA was preceded by other regulatory oversight bodies in the Nixon, Ford and Carter administrations. But the process of actually reviewing rules, and changing them, began when the office was set up under the Paperwork Reduction Act of 1980 and President Ronald Reagan gave it the authority.

"My role at OIRA was to say, 'Stop,' " Miller said. "We told them [the agencies] what they had to do to pass muster. We put in a filter that said rules had to have a certain substance and meet certain criteria."

Gary Bass, founder and executive director of OMB Watch, a public-interest group created in 1983 in part to monitor OIRA, said the office was "the Marine Corps of agencies" in its early years. "They would come in and run right over you. They overrode the agencies. They threatened budget cuts."

The U.S. Chamber of Commerce said the Reagan administration used the office effectively as a traffic cop. Since then, said William Kovacs, the chamber's vice president of regulatory affairs, OIRA administrators have had varying degrees of success in controlling the output of rules, supervising the agencies and supporting the business community in Republican administrations.

"The agencies still run the show. They have the expertise and the scientists. They can baffle them at OIRA," he said.

Public-interest groups take the opposite view.

Thomas McGarity, a scholar with the Center for Progressive Reform, which advocates effective use of government to protect people, said there is no oversight of OIRA by the current Republican Congress.

McGarity said the office's administration of the Data Quality Act, which passed in 2000, allows outside challenges to data used by federal agencies in rulemaking and has "tremendous potential for mischief."

Some public-interest groups credit Graham's tenure for bringing more transparency to the process of rule review. Meetings with outside parties are listed on the office's Web site, as are correspondence with agencies. But they still think OIRA decisions usually favor corporate interests.

"It used to be a sledgehammer approach; now it's an ice pick. It's more sculpted and surgical," said Bass, comparing the treatment of rules in earlier Republican administrations with this one's.

Graham said when he took the job in 2001 that OIRA would act as more of a gatekeeper than a counselor -- as it had in the Clinton years when the review process with the agencies was more collegial.

He made cost-benefit analysis and risk assessment paramount in the creation and review of rules and drew heavy criticism for promoting what came to be known as the "senior death discount." This was an analysis that placed less monetary value on an older person's life.

He issued guidelines for how scientific information should be peer-reviewed. And he hired new experts in the areas of toxicology, epidemiology, public health, engineering and risk assessment -- allowing OIRA to better go head to head with agency expertise.

Graham and his staff sent back 26 agency rules, compared with 13 during the Clinton years and 290 during the Reagan administration. Increasingly, OIRA worked with agencies early in the review-writing process, signaling that early cooperation might avoid a return letter later.

Robert Hahn, director of the Joint Center, a project of the American Enterprise Institute and the Brookings Institution, said he hoped this alumni reunion, of sorts, will be the forum for a serious retrospective where "we engage these folks in a constructive dialogue about what they did right or wrong and how to improve things."