On the wall of Rep. Terry L. Bruce's (D-Ill.) congressional office is a photograph of Rep. John D. Dingell (D-Mich.) peering over a chessboard. Bruce hung the picture out of gratitude to Dingell for getting him on his Energy and Commerce Committee and as a tribute to a politician who knows how to exercise power.

If there is one lesson that Dingell has pounded home to his protege, it is the importance of building political coalitions to get what he wants. In his three terms in Congress, Bruce has applied the dictum to his advantage in many legislative fights, but never more effectively than last spring when, as the committee was drafting a new clean air bill, Bruce challenged the master himself.

In need of allies to accommodate the diverse interests of his downstate Illinois district, Bruce initially sided with Dingell's pro-industry coalition. But when their objectives parted, so did Bruce, defecting with farm bloc allies to the environmentalists after Dingell refused to carve out a big role for gasoline substitutes made from corn. Having outflanked Dingell, he went on to forge alliances wherever the needs of the 19th district took him, joining Texas lawmakers to shield low-producing oil wells from regulation, labor unions to save coal mining jobs from acid rain controls and conservative Republicans to protect small business from smog controls.

His coalition building not only benefited his own constituents, but helped bridge the deep divisions that have kept Congress from passing clean air bills for a decade. In the process, however, he forgot another fundamental Dingell lesson: No deals are final without the power to sustain them. And so when it came time for the chairman and chess master to select members of the conference committee that can change the product of months of painstaking negotiation in a few minutes, Dingell made sure that Bruce was not on it.

The education of Terry Bruce is not simply the story of a congressman's disappointment. It illustrates the difficulty of putting together lasting coalitions to pass complex legislation affecting a broad range of conflicting political and economic interests. It also suggests why final congressional passage of new clean air laws, after nearly 14 months of debate and approval by both the Senate and House, is far from certain by adjournment next week.

The first sign of progress in weeks in the conference committee occurred Wednesday when staff members reached a tentative agreement on auto pollution controls. The accord, if ratified by members, would remove a major obstacle. But since then talks bogged down over controls of industrial toxics, one of several thorny issues left for conferees as they struggle to finish work by the Monday deadline set by congressional leaders.

Passing the first new clean air bill since 1977 did not seem so forbidding a task in July 1989 when President Bush introduced the administration bill that would become the framework for the ensuing debate. The bill had three main objectives -- curbing urban smog, imposing a nationwide cap on the ingredients of acid rain and limiting cancer-causing industrial emissions -- that it is estimated would cost industry $25 billion to achieve through the installation of new technology and changes in manufacturing processes.

No one knows the political costs of clean air better than Bruce, 46, an ambitious, three-term congressman from the expansive farms and small, old-fashioned towns of southeastern Illinois. Nearly every polluter targeted for controls in the bill -- oil, auto, petrochemical, coal, utility, chlorofluorocarbons (CFCs) and consumer solvents -- has plants and workers in his economically strapped district. But Bruce cannot survive politically by catering to industry. A Democrat in traditionally Republican territory, he could not have won his seat in 1985 without the backing of environmentalists concentrated at the University of Illinois in Champaign-Urbana.

If he was in a tighter box than most lawmakers in the clean air fight, Bruce, as a member of Dingell's committee, was also in a better position to extricate himself.

In the past, the 43-member committee has been a bottleneck of clean air legislation because of the heavy concentration of lawmakers from industrial states. As a protege of "the chairman," as he is always known, Bruce traditionally backed Dingell on clean air issues, and opposed efforts by Rep. Henry A. Waxman (D-Calif.), an environmentalist and long-time Dingell rival. But with passage of legislation likely this year and pressures from his district mounting, Bruce knew he would need help, particularly since the bill would contain the first measures designed to fight acid rain.

In a district of so many concerns, acid rain seemed to touch most of them: environmentalists who want it cleaned up, utilities whose emissions are its cause and the miners who supply them coal.

Along with other midwestern congressman, Bruce's first priority was seeing that the utilities received some financial assistance in return for any antipollution efforts they might be required to make. The subsidies they hoped to obtain would be used to limit rate increases for local homeowners and businesses and save jobs. Technology made affordable by the aid could clean up the emissions from the burning of high-sulfur coal by the utilities.

In February, Bruce helped Rep. Philip R. Sharp (D-Ind.) draft a proposal to pay for the subsidies by taxing industrial, non-utility sources of acid rain nationwide. Sharp had hoped to get approval from the subcommittee he chairs, and was promised help by Dingell if the vote was close. The indication was that Rep. Ralph M. Hall (D-Tex.), Dingell's loyal ally and fly-fishing buddy, could be persuaded to help the midwesterners in a pinch.

Nearing a majority, Sharp and Bruce turned to Waxman, who agreed to release one of his allies in exchange for three midwestern votes on an anti-smog provision.

Figuring that they were within a single vote of victory on the subsidies, the time was ripe to call in Dingell's pledge. But when Bruce went to get it, Dingell had bad news. "He said that he met with Hall and couldn't get him," recalled Bruce. "He said, 'There's nothing I can do for you.' "

Fresh from his disappointment on acid rain, Bruce focused on another issue of critical importance to his district -- Bush's proposal to encourage the use of alternative fuels. Ethanol, the grain-based substitute for gasoline, was seen by Illinois farmers as a way to open up a new market for their corn. Bruce wanted Dingell to increase the number of polluted cities where motorists would be required to use ethanol, and made his case with the chairman. But when an aide came back with an answer, the news was again bad -- he offered just 21 cities instead of the 44 Bruce had pressed for.

Twice burned, Bruce and his allies met to discuss strategy. Acid rain would be up again for consideration -- this time by the full committee, the last major provision of the bill on the agenda -- and they feared that the process was moving so quickly, with members cutting deals on other issues to satisfy their interests, that the midwesterners would have no leverage to get any help.

If they were ever going to be able to come back to the subsidy issue, they needed a new ally. If Dingell refused to play, Waxman might, on clean fuels as well as acid rain. Bruce said: "We weren't going to be good soldiers and not get anything out of it. We intended to jolt {Dingell}."

By siding with Waxman's environmental bloc on clean fuels, a motor vehicle issue important to Dingell and his Detroit-area district, they risked alienating the powerful chairman. But Dingell posed a real danger if he felt betrayed on an issue so important to automakers. Bruce decided to go ahead anyway, and joined with Waxman in support of "reformulated gasoline," a cleaner-burning fuel to be sold in 44 polluted cities -- twice as many as Dingell's latest offer.

Dingell called the committee into session an hour after the agreement. Apparently sensing that the momentum was swinging to Waxman on clean fuels, Dingell called Bruce to the podium. Leaning forward in his chair, he angrily reminded Bruce how he got on the committee, how he had been invited to accompany Dingell on official trips to Europe and Central America and how his prospects to move up the ranks were in Dingell's hands.

With the opposition gaining, Dingell quickly called the roll and won by a single vote. But the victory was short-lived. When, a month later, the bill finally got to the floor, where Dingell has less influence, the same coalition of farmers and environmentalists was too powerful to stop, and he was forced to accept the basic terms of the amendment.

When the committee turned to acid rain, Dingell was not in a much better position, having committed himself to members with contradictory interests. The committee was split between lawmakers from "dirty" states such as Illinois and those from "clean" states, mostly in the West and Southwest, whose utilities had switched to clean fuels or technology years ago at great expense and were not about to share the cleanup costs of big polluters elsewhere.

Dingell declared his neutrality, but by letting negotiations go on, he gave the midwesterners time to overcome their large disadvantage in voting strength and eventually wring key concessions from the clean states.

The very act of crossing Dingell on clean fuels appeared to have gotten his attention -- as Bruce had predicted. Once vital parts of Dingell's coalition, the midwesterners' independence "showed they couldn't be taken advantage of," said Rep. Jim Cooper (D -- Tenn.), a leader of the clean states.

Having abandoned any hope of outright subsidies for antipollution devices at midwestern utilities, Bruce's group turned its attention to a mechanism in the administration bill designed to partially reimburse the dirtiest plants, the ones targeted for the biggest cuts in emissions.

For every ton cut below emission limits, they would receive a credit to be banked for later use or sold to other utilities seeking to expand operations. There was no comparable mechanism that would allow plants that were already clean to expand unless they bought credits from polluters.

Committee members from the clean states wanted credits for their utilities without having to buy them. The midwestern contingent led by Bruce and Sharp wanted credits as a way for their utilities to cover their costs and didn't want their reward for cutting emissions given away.

The negotiations amounted more to a barter, and credits were on the block. Dirty states had them; clean states wanted them. So did a large number of relatively clean utilities in other states that claimed they were shortchanged in the amount of emissions they would be allowed every year.

As the talks began, Bruce instructed the staff: "Solve the problem, get the vote." The concessions -- in the form of credits -- were tucked into larger proposals sent to the Republican lounge, crafted in arcane legislative language intended to cover only the intended beneficiaries: 40,000 tons a year for Florida utilities to accommodate the state's spurt in population and appease Rep. Michael Bilirakis (R-Fla.); 8,900 tons a year to cover a Baltimore Gas & Electric plant under construction and win over Rep. Tom McMillen (D-Md.)

With the balance shifting in favor of the Midwest, Bruce decided to go after the vote of Rep. J. Alex McMillan (R-N.C.), who had lined up with the coalition of clean states. McMillan's utility, Duke Power, complained that the method for determining credits was unfair to the company and denied it a fair share. On the night of April 4, as dozens of lobbyists milled outside the committee room, Bruce's group floated a comprehensive proposal with a specific provision devised for Duke Power, offering what appeared to be 35,000 tons per year in credits.

"I went out to Duke Power's lobbyist and said, 'We've taken care of your problem. Make sure we get the vote,' " recalled Michael Bushman, a Bruce aide. "A half hour later, McMillan showed up in our room."

It turned out to be the final blow for the clean states -- they had no choice but to compromise.

The negotiations ended with a package of concessions for midwestern utilities more generous than the Senate had approved. Plants would receive two credits for every ton of emissions they cut below the new limits by using technology -- a major concession to high-sulfur coal -- and another year in which to comply by using the devices. Governors would have the right to mandate use of coal mined in their states.

By playing Waxman against Dingell, Bruce ended up with more then he would have gained if he had lined up consistently with either. But he paid a high price for his independence when it came to the final and ultimately most critical round in passing the bill, the conference.

In a heated meeting a few days before the team was announced in late June, Bruce got the news from his old mentor. According to Bruce, Dingell was blunt. If Bruce felt compelled to vote his district interests in committee, how could he be trusted to follow Dingell's lead through the thicket of conference issues?

Dingell, in an interview, said that loyalty was "one of the important tests" in his selection of conferees but that Bruce did not fit the geographic criteria or play a role in the kind of issues necessary to balance the House team.

All summer and now into the fall, Bruce has been relying on a network of supporters to protect his district's interests inside the conference. But that is no substitute for being at the negotiating table, where a quick decision to delete a line from the bill or add a phrase can cost a utility millions of dollars, close a coal mine or limit new markets for corn-based ethanol.

Dingell, of course, is at the head of the table.

"I played by one set of rules," Bruce said, "and he played by another. Good deeds do not get rewards unless they're his good deeds."