He had promised in the 1988 campaign to use "the White House effect" to fight the "greenhouse effect," but as President Bush sat down with a dozen advisers at the White House last April he confronted an issue to which he had given little personal attention during his presidency.

While environmentalists had warned of a potentially devastating peril to the world climate from the buildup of heat-trapping gases, and scientists -- joined by Bush's former chief of staff John H. Sununu -- had engaged in a sharp public debate over the accuracy of such predictions, the president had remained aloof. But in April, with an environmental summit meeting due to convene in Rio de Janeiro six weeks later, Bush was faced with a difficult diplomatic problem: The U.S. position on the first international treaty to deal with global warming was sharply at odds with the rest of the industrialized world.

As his advisers reeled off the economic, environmental and diplomatic implications of the treaty, Bush sat silently, showing little interest in the issue, participants at the meeting recall, until the discussion turned political: Congressional Democrats were threatening to embarrass him by legislating the very terms his negotiators were opposing.

"Since when does Henry Waxman run the government?" he asked, referring to the liberal California congressman who was sponsoring the legislation.

In June, when the Earth Summit took place, the public disagreement between the United States and its allies resulted in a public relations disaster for the Bush administration at a critical time in the presidential campaign. A reconstruction of the global warming policy debate at the administration's highest levels offers an insight into the way Bush addressed complex domestic concerns.

In background interviews with two dozen officials involved in setting policy on global warming, Bush was described as being detached, uninterested, and as his brief remarks in the April meeting showed, responsive only to the politics of a complex issue. He never sat for a full-dress scientific briefing on it or exercised control over administration policy even after infighting among administration officials became public or leaders of other industrialized nations pledged action.

Instead, he delegated policy decisions on global warming, as he did on other key economic and social issues, to Sununu, a conservative former governor of New Hampshire.

In the absence of any presidential involvement, Sununu followed his personal belief that global warming projections were alarmist and overruled the recommendations of the administration's own environmental officials. Stressing his engineering credentials, Sununu commissioned government-supported scientists to develop a simplified climate model that he ran on his office computer. His strong arguments -- even in the face of contrary scientific evidence -- that excess heat from the burning of carbon fuels would be absorbed by oceans earned him the nickname "plankton man" from the president.

Scientists generally agree there is a warming trend, but their estimates of how fast and how far the planet will heat up vary widely. Rather than recognize an emerging consensus, Sununu seized on the differences in opinion as a reason to avoid action and turned global warming into an issue to be politically finessed. When criticism of the president would intensify, the White House responded by taking public relations measures, such as issuing an "action agenda" that repackaged existing policies and plans to plant trees that absorb the primary greenhouse gas.

"We debated tactics," one former White House official said, "but there just was no examination of the core elements of policy."

Sununu squelched a full-scale debate on the issue, engineering the firing of a deputy assistant secretary of state who argued for a more aggressive policy, and got so deeply involved in the politics of the issue that he planned a White House workshop on global warming right down to the hiring of a Republican conventions expert for $24,000 to handle the logistics, choosing speakers, editing press releases and demanding hourly reports.

No one else in the administration had the power or access to challenge him. Secretary of State James A. Baker III, an early proponent of action on global warming whose department was intimately involved in international negotiations on the issue, recused himself in early 1990 from any policy decisions because of his investments in oil companies.

After Sununu resigned last December and U.S. negotiators were more intent on reaching accord, politics still was a driving factor, this time out of the need to avoid alienating the Republican right just as conservative Patrick J. Buchanan was challenging Bush in the presidential primaries.

Bush eventually approved a global warming treaty tailored to meet U.S. demands for a narrower, less specific pact than most other nations wanted. It set approximate deadlines and limits on emissions of greenhouse gases, but failed to explicitly link the two.

The accord is nonetheless considered a decent start, and perhaps a prudent one -- given the usual fickleness of science.

But Bush's involvement in developing the accord was minimal. When European Community President Jacques Delors at a White House visit in April tried to break a deadlock with a last-minute compromise, Bush responded with only a few words and moved to another topic. When top aides asked his approval of treaty language, he threw up his hands in frustration at the technical details as if he could not be expected to understand them. And lunching with advisers a few days before the treaty signing in Rio de Janeiro, he asked, "Tell me again, why is it we couldn't do what the rest of the world wants to do."

Issue Divided Administration

To some extent, Bush acted like any president in relying on his advisers to direct key issues. If he differed in his approach to such domestic concerns as global warming, critics say, it was his failure to ride herd on the staff and take charge of major developments.

The issue drove his advisers into factions, dominated for the first three years by Sununu, who declined to be interviewed for this article. Sununu had powerful allies in Richard G. Darman, director of the Office of Management and Budget, and Michael J. Boskin, chairman of the Council of Economic Advisers. They argued that limits on greenhouse gases, produced by burning oil and coal, would be economically ruinous because of U.S. dependence on those fuels. As Boskin warned before the 1990 economic summit in Houston, "Remember, Mr. President, this is a bet-your-economy issue."

Heading the environmental camp was Environmental Protection Agency Administrator William K. Reilly, a career conservationist who sought a more detached analysis of the scientific forecasts and called for energy conservation measures that would carry their own economic benefits while reducing warming gases.

An occasional ally of Reilly's was Robert E. Grady, then head of environmental programs for the OMB, who wrote Bush's environmental speeches in the 1988 campaign, including the now-famous promise in Michigan to use the "White House effect" to combat the "greenhouse effect."

In the center was a faction of pragmatists, led by Clayton Yeutter, the short-lived domestic policy coordinator under former White House chief of staff Samuel K. Skinner. Yeutter took charge of the issue after Sununu left. By bringing together warring parties last spring, he managed to find enough common ground for a pair of results-oriented diplomats to negotiate a treaty in time for the Rio summit.

After Baker recused himself in 1990, he handed the issue to Robert B. Zoellick, the State Department counselor. A Darman protege and Bush campaign aide in 1988, Zoellick had good standing in both the White House and the diplomatic community.

Zoellick's chief negotiator was Robert A. Reinstein. Blessed by background and politics, his career in energy and trade included work for Yeutter, who recommended him as deputy assistant secretary of state for the environment, after Sununu forced the firing of his predecessor, William A. Nitze.

Campaign Call for Action

Ironically, Bush was one of the first world leaders to warn of global warming when he pledged Aug. 31, 1988, to "do something about it" and called for an international agreement.

But like other promises that later haunted him, the global warming pledge was born out of political considerations. He picked the issue out of a briefing book that aides had brought to the vice president's mansion to gear up for the environmental vote. Turning the pages, Bush said, "Let's try this one."

His timing was right: 1988 was the warmest year on record, joining five earlier record-breaking years, and it focused interest on environmental issues. Scientists said it signaled a long-term trend in which world temperatures would rise at least 3 degrees by about 2050, causing floods in some places, droughts in others.

But when the new administration had its first chance to act, it balked. In May 1989, a diplomatic panel formed by the United Nations was set to meet in Geneva. Reilly suggested support for a framework treaty to define the problem and its remedies.

Sununu blocked the idea, arguing that the threat was too tenuous and the cure too costly to start down the path of international agreements.

It was a Pyrrhic victory for Sununu. Newspapers reported the Reilly rebuke, plus stories that OMB diluted global warming warnings in the congressonal testimony of a respected federal scientist. Members of Congress asked, was this the "White House effect" Bush had promised?

A chastened Sununu called Reilly to the White House late one evening. The president was embarrassed, he said, "What do we do?" The EPA chief suggested committing to a framework convention and offering to hold the first negotiating session here.

Only a week earlier, Sununu had rejected a similar proposal. But now he ran the idea by Bush, a former aide recalled. "Whatever you both think is necessary," the president said, and the announcement was made. The United States thus had been committed, in reaction to political criticism, to participating in an international event that top presidential advisers still opposed. Politics paved the way to Rio, but the failure to resolve the substantive differences resulted in more political infighting.

Although Sununu retreated to quiet critics, he was determined to hold the line in any treaty to simply identifying the problem and listing possible remedies without committing the parties to any concrete action. He put White House science adviser D. Allan Bromley, rather than Reilly, in charge of coordinating global warming policy.

Sununu consolidated his control after Baker withdrew from involvement in the issue. The secretary of state recused himself after Sununu tore up and rewrote a Bush speech that Baker, Reilly and Energy Secretary James D. Watkins had approved for delivery to a global warming meeting here Feb. 5, 1990.

The president delivered Sununu's draft, stressing the "scientific uncertainty" of global warming and the U.S. commitment to spending more on research.

But as diplomatic criticism mounted and a U.N. panel of 300 climate experts projected unprecedented temperature rises if nothing is done, Bush continued to defer to Sununu and did not personally engage the issue.

He invited environmental officials to the White House but when global warming came up, he changed the subject. At one point Bush encountered aides in an informal gathering and broached the issue, but he exited quickly as the discussion got technical, saying, "Let me know when you get it figured out."

By the opening of treaty talks in February 1991, European nations raised the ante. Instead of a hollow framework convention, they wanted a treaty with "targets and timetables" to stabilize emissions of the main greenhouse gas -- carbon dioxide -- at 1990 levels by the year 2000.

The administration called for nonbinding "national action plans" to level off all greenhouse gases, not just carbon dioxide, the industrial byproduct of burning coal and oil. The negotiations remained at a stalemate until Sununu resigned in December 1991.

Clamor for a Treaty

When Yeutter took over domestic policy last February, he saw a crisis brewing. The Rio summit was four months away, and every other industrialized nation was clamoring for a treaty to sign there. He found the decision-making process frozen, with the president uninformed and his advisers badly split. Reilly and Grady favored some form of stabilization, and Darman and Boskin argued against a treaty and summit. To complicate matters, Buchanan was running well in early primaries and was bashing environmental issues.

Yeutter knew how much Bush enjoyed the pageantry of state visits, but if there was no treaty, the president would be held accountable at Rio. If he accepted "targets and timetables," he faced conservative criticism at home.

A treaty acceptable to both sides had to be worked out.

Reinstein enlisted help from British officials at an April meeting of industrialized nations in Paris. On April 29, two days after Bush's briefing, British Environment Minister Michael Howard came to Washington to go over final details of a compromise with Zoellick and Reinstein. When they emerged, they had a deal: "Targets and timetables" were replaced by nonbinding, unspecific goals that left much room for interpretation.

Before the language could be formally presented at the last round of talks prior to Rio, Yeutter had to get the president's approval.

In the Oval Office, he explained how the compromise was carefully devised to permit the president to go to Rio without committing the nation to drastic economic measures. According to an observer, Bush threw up his hands at the technical details, asking "How is anyone supposed to understand this stuff."

But 15 minutes later, he ruled: "Let's try it."

Reinstein took the next shuttle to New York in time to have the new language unveiled in the last round of talks before Rio.

On May 8, agreement was reached. The language worked out by Zoellick and Howard was refined into what Jean Ripert, who chaired the U.N.-sponsored talks, called "constructive ambiguities." Industrialized nations agreed to submit reports "with the aim of returning" to 1990 levels of greenhouse emissions. But no deadline was given for reaching the goal.

Still, other governments, as eager as Washington to make the Earth Summit succeed, saw it as their best chance for the first global warming treaty. Only after agreement was reached in New York did the White House announce that Bush would attend the Rio conference.

While the treaty was being wrapped up and the White House was making arrangements for Bush to go to Rio, the administration continued to manage the issue politically. To assuage conservative concerns, Yeutter wrote a letter May 8 to the powerful chairman of the House Energy and Commerce Committee, Rep. John D. Dingell (D-Mich.), explaining that the key language in the pact was contained in two sections.

"Neither binds the United States to specific commitments of any kind," he said.