At a gathering of health care executives two weeks ago, the industry's chief lobbyist, Michael David Bromberg, rose from his chair and delivered a blunt warning to the guest of honor, Hillary Rodham Clinton. His message: If we can't work with you, we'll have to campaign against you.

An angry Hillary Clinton is said to have left the meeting shortly afterward. It was a signal that the great health care battle of 1994 was about to begin.

The health industry won a key opening round of the fight last week. Despite pleas from the White House, the influential Business Roundtable voted to support a milder reform plan proposed by Rep. Jim Cooper (D-Tenn.). Working behind the scenes to round up support for the Cooper plan was the 55-year-old dean of Washington health lobbyists -- Mike Bromberg.

Bromberg has been preparing for this moment for nearly 30 years. In quarterbacking the industry's opposition to the Clinton plan, he typifies the new breed of lobbyists, and how they play the legislative game.

Although most people have never heard of him, Bromberg may be the man to watch as Congress wrestles with the issue that will affect every American. His clout extends far beyond the 1,400 for-profit hospitals and investor-owned health care companies he has represented for the past quarter century as executive director of the Federation of American Health Systems.

His influence is largely a product of four things: an encyclopedic knowledge of both politics and policy; a shrewd sense of timing; enviable access to key Democratic and Republican members of Congress and their staffs; and money from the federation's hospitals, which fund one of the industry's leading political action committees, one that gives $250,000 every two years to House and Senate candidates.

His reputation was cemented nearly 15 years ago when he masterminded the legislative strategy that led to the humiliating defeat of a health reform plan proposed by the last Democratic president -- Jimmy Carter -- who sought to rein in skyrocketing hospital costs by imposing mandatory price controls.

"He's one of the best," said Rep. Dan Rostenkowski (D-Ill.), Bromberg's most important patron on Capitol Hill. It was Rostenkowski, the powerful chairman of the Ways and Means Committee, who advised a reluctant Hillary Clinton to meet with Bromberg last August -- their first stormy encounter -- telling her that while she might regard Bromberg as the enemy, she would be negotiating with him in the end because they would need each other.

Thirty years ago, being a Washington lobbyist was a much simpler proposition; men with bags of money prowled the Capitol, currying favor with people such Bobby Baker, the Lyndon Johnson protege who went to jail on charges of tax evasion in connection with an influence-peddling scheme.

These days, corporate lobbyists, and particularly the cadre of superlobbyists to which Bromberg belongs, use the same tools as managers of political campaigns: tracking polls, advertising and public relations campaigns, focus groups, visits to newspaper editorial boards; appearances on television news talk shows; and torrents of letters, phone calls and faxes from "grass-roots" constituents.

"Lobbying does not necessarily mean going up to the Hill eight hours a day and hanging out," observes Deborah Steelman, a former associate director of the Office of Management and Budget in the Reagan administration, now a Washington lawyer. "And it's not about going up and tugging on Rosty's sleeve and saying 'I need something.' That gets you absolutely nowhere. It's knowing how to mobilize, having access to information, making the right moves at the right time. Mike is a master of this."

In many ways Bromberg is atypical of the first rank of lobbyists, although his 1993 salary and benefits package, totaling $405,000, places him squarely in that category.

He is not a hired gun who works for a law firm or a lobbying shop and is brought in by a client to help pass or defeat a bill. Nor is he an example of the revolving door -- a lobbyist who shuttles between high-level jobs in government and private industry, as an increasing number of Washington's 5,000 registered lobbyists do.

He doesn't wear Gucci shoes, a gold watch, custom-made suits or monogrammed shirts, the sartorial standard of corporate lobbyists, most of whom are men. And while he can be funny, charming and generous, he is unfailingly direct and seems allergic to small talk, embarrassed by praise, and is sometimes impatient to the point of brusqueness.

He is more dealmaker than ideologue, and has counted among his friends the late Allard Lowenstein, the reform Democrat best known as an architect of the 1968 "Dump Johnson" movement, as well as Senate Minority Leader Robert J. Dole (R-Kan.), whom Bromberg backed for president.

Bromberg's "tough, but when the time comes, he's prepared to make a deal," said one veteran Capitol Hill staff member who has worked with and against him.

Bromberg has made at least one high-profile enemy: Rep. Fortney Pete Stark, the maverick California Democrat who chairs the health subcommittee of Ways and Means and refuses to speak to Bromberg or his staff for reasons that a source close to Stark says are "shrouded in ambiguity." Stark declined to be interviewed but others close to both men say the rift stems in part from Stark's view of profit-making hospitals, which he regards as avaricious. Bromberg will only say that Stark is "very effective."

His problems with Stark don't seem to have mattered much. Once a month, he and four other lobbyists whom he declines to identify have dinner with a different senator at a private club in Georgetown. He is on a first-name basis with many members of Congress and counts among his neighbors in the exclusive Kalorama section of Washington Treasury Secretary Lloyd Bentsen, White House chief of staff Thomas F. "Mack" McLarty and Sen. Diane Feinstein (D-Calif.).

For many years, the Brombergs have given $1,000-a-plate fund-raising dinners at their home on behalf of one Democrat and one Republican member of Congress. Beneficiaries have included Sens. David Pryor (D-Ark.) and Dave Durenberger (R-Minn.), both of whom are influential on health care issues. They also host lavish semiannual treasure hunts for about 30 guests, most recently at the weekend house they built in Rappahannock County, Va.

How much clout all of this will give Bromberg as Congress struggles with the extraordinarily complex, politically charged issue of health care remains to be seen. Bromberg acknowledges that this is the most important fight of his career. In 1988, he concluded that reform was inevitable and help found the Healthcare Leadership Council.

Headquartered in an expensively decorated suite two blocks from the White House, the HLC is an exclusive club and one that poses a formidable challenge to the Clinton administration's hopes for its brand of reform. Its membership is limited to the chief executives of 50 of the largest health care companies -- drug manufacturers, hospital chains, medical suppliers, managed care and insurance companies.

Bromberg and David A. Jones, chief executive of Humana Inc., founded the group in 1988 to ensure that the titans of the "medical industrial" complex could continue to thrive under health care reform.

"We knew then that another few years of stalemate and we'd be walking ourselves straight into Canada," said Bromberg, referring to the "single-payer" government-financed system that he and his allies regard as their nightmare. "It's in our interest to get something passed to slow down this infatuation with Canada."

The HLC's goal is simple: to minimize government regulation in any bill that does pass. Thus, its support for Cooper's bill, which doesn't include the Clinton plan's spending caps, its mandates that employers buy insurance for their workers or its requirement for universal coverage with a defined benefits package. The Cooper approach has been dubbed "Clinton Lite," and that seems to be about what Bromberg wants.

To increase support for this approach, the HLC months ago targeted 100 House members and 15 to 20 senators, most of them moderate Democrats in eight key states -- Texas, Louisiana, Alabama, Virginia, North Carolina, South Carolina, Florida and Georgia. These, said Bromberg, are the same states targeted by the "other side" in its campaign to sell the Clinton plan.

Bromberg learned his most important lessons about lobbying 30 years ago when he served as the campaign manager and administrative assistant to Rep. Herbert Tenzer, a liberal Democrat who represented a largely Republican district on Long Island from 1964 to 1968.

Every weekend, Tenzer went back to the district. The first thing he did upon his return to his House office was to empty his pockets of the scraps of paper and used envelopes on which he'd jotted down things that needed to be done back home.

"That's where I learned that grass roots -- paying attention to things in the district -- was more important than all the myths of Washington lobbying," Bromberg said. "That, plus running a campaign -- that's when you really see what influences a member of Congress. You see (a) how easy it is and (b) how much better it is if it's local."

Careful cultivation of grass roots, he said, is a lobbyist's only hope of countering the awesome powers of presidential patronage.

Running Tenzer's 1964 campaign was Bromberg first foray into politics. The only child of largely apolitical parents, Bromberg graduated from Columbia University in 1958 with a degree in English and flirted with careers as a reporter and a musician -- he sang with a group that included Art Garfunkel -- before opting for law school. He received his law degree from New York University in 1962 and went straight to work for Tenzer's Manhattan law firm.

When Tenzer retired from Congress in 1968, Bromberg was urged to run for his seat. He declined and Lowenstein was ultimately elected. "I never wanted to be the packaged candidate," Bromberg said. "It's like a chess game. It's better to be a chess player than the pieces."

For a year, he served as the Washington office for Tenzer's firm. In 1969, he became the first and so far the only executive director of the fledgling trade association representing for-profit hospitals that were springing up with the advent of Medicare, the federal health insurance program for the elderly.

"Editorials are the key to this thing," Bromberg was explaining during a trip to Texas last June to build support. He was seated in the back of a limousine, punching buttons on a portable phone, heading to Fort Worth for a meeting with editorial writers at the Star Telegram, then back to Dallas for a meeting with the editorial board of the Morning News.

"We need to give people a reason to vote against the president if necessary," he continued. "The only way a guy can say no to the president of the United States is to be able to say the people in my district, the opinion leaders, are against it. He needs those editorials for cover."

In Fort Worth, Bromberg slid easily into his criticism of global budgets and price controls. He handed the editors a chart that listed per-capita spending by states. Bromberg argued that spending caps will lock states into this pattern, rewarding big spending states such as Massachusetts and penalizing others, such as Texas, which ranks 32nd.

"It's outrageous," Bromberg told them.

Ninety minutes later, he gave the same pitch to the Dallas Morning News. When one writer suggested that spending caps might be a good way to limit runaway health costs, Bromberg quickly countered: "You can't put a cap on spending until you put a cap on illness, or crack babies or gunshot wounds. That's rationing, that's what they do in Canada."

In Dallas, at least, his efforts appeared to have paid off. On Sept. 23, the morning after Clinton gave his health care speech, the Morning News ran an editorial that applauded the Cooper bill.

Bromberg watched the president's big speech on health reform last September while sprawled on a leather sofa in front of his 46-inch television set, a yellow legal pad at his side. By that time, he had already won some small lobbying victories. After half a dozen meetings with White House officials, including Ira Magaziner, he had won his case that the Clinton plan should not include a tax on hospitals and mandatory short-term controls on hospital prices, which appeared in an early draft of the plan.

Several reporters arranged to call him for reaction; ABC News's "Nightline" asked him to stand by for a possible appearance on the show, which ultimately did not materialize.

Seconds after the long speech ended -- and several minutes before the first reporter called -- Bromberg triumphantly announced that he had decided what "sound bite" quote he would feed the media: "It's a fantastic speech, but you don't vote on a speech. Where are the details?"

If Congress manages to pass a bill this year, will it bear Mike Bromberg's imprimatur? At this point, his opponents are not betting against him.

"Mike Bromberg and other lobbyists are going to have a very important role to play in formulating a plan," said Rep. Henry A. Waxman (D-Calif.), one of 100 House sponsors of the Clinton plan, carefully choosing his words.

One veteran Democratic congressional staff member who has worked against Bromberg for much of the past 20 years explained his fears: "Hospitals are often the largest employers in any district and, rightly or wrongly, are viewed as pillars of the community," he said. "And I think Bromberg can turn them out. So he will play those anti-regulation, pro-competition cards, which are a very powerful argument with members. And I fear he's going to prevail."

Rostenkowski, who remains Bromberg's chief congressional patron, explained his leverage on the system with a medical metaphor: "We're not the experts; he's the expert," the chairman of the Ways and Means Committee noted. "We're the general practitioners."