Just hours after Iraqi tanks rolled into Kuwait, oil industry allies in the Senate seized what appeared to be a golden opportunity. Invoking the threat of energy shortages, Sen. Frank H. Murkowski (R-Alaska) tacked on an amendment to the defense authorization bill that could dramatically expand oil exploration in sensitive federal lands.

The amendment, approved in a late-night session after virtually no debate, would grant the president far-reaching power to bypass environmental restrictions if oil imports exceed 50 percent of U.S. consumption.

While the measure must still pass the House, environmentalists fear that it could foreshadow a reversal of their recent, hard-won gains. Just as issues such as global warming and deforestation have become part of the public agenda, the nation suddenly faces the prospect of gasoline lines, military conflict and economic downturn, raising anew the question of how far Americans are willing to go to protect the environment when confronted by more immediate threats.

"I don't think it would be proper to look at environmentalism as a luxury to be dispensed with, but I do think it will be harder to maintain it as a priority," said David Alberswerth of the National Wildlife Federation. "We may have to do more work to convince people it's in their long-term interest."

Already, the oil industry is trying to prod Congress into lifting restrictions on oil drilling in the fragile Arctic National Wildlife Refuge; the Energy Department is pressing California officials to grant the necessary permits for a massive new oil development off Santa Barbara, and industry lobbyists are hoping to ease proposed pollution controls in pending clean air legislation.

If the past is any guide, turmoil in the Middle East spells trouble for environmentalists, who watched Congress and the executive branch whittle down the Clean Air Act and push for more domestic oil development during oil shocks of the 1970s.

But there are important differences today. The environmental movement is far stronger after a decade of burgeoning memberships and budgets. Public interest in the environment has been driven to historic highs by growing scientific evidence of global climate change and several costly disasters, especially the Exxon Valdez oil spill last year in Alaska. Politicians from the White House to the courthouse have taken their cue, lining up with industry to mark the recent celebration of Earth Day.

Indeed, many environmentalists view the Persian Gulf crisis as an opportunity. They have been busy staging news conferences and writing press releases citing the Iraqi invasion as a reason to develop renewable energy sources and conservation measures.

"We can't pump our way out of this crisis," said Daniel Becker of the Sierra Club, touting a bill that would require a near doubling of auto fuel efficiency by the year 2000.

Even within the conservative Bush administration, advocates of clean air legislation have begun to prepare a defense against probable arguments by industry that this is no time to impose costly new regulations. Officials were anxiously generating data last week showing that several provisions will actually reduce oil use, including regulations to replace gasoline with cleaner fuels and force utilities to stop burning oil that contributes to acid rain.

"Environmental concerns are just too strong now for any political leader to quickly dismiss them," said Lester R. Brown, president of Worldwatch Institute. "We're very much aware of the short-term diversion but also aware that our issues are long-term and very real."

Industry, sensitive to the public relations appeal of environmental issues, has been reluctant to openly exploit the current mood. The American Petroleum Institute, for example, turned down requests to interview executives on the issue. "We are not Johnny-come-latelies trying to exploit this crisis," said an API spokesman.

But such reservations did not stop API President Charles J. DiBona from urging Congress only days after the invasion to step up oil exploration in sensitive areas and relax recent federal requirements to reduce smog produced by gasoline.

Richard Rahn, vice president and chief economist of the U.S. Chamber of Commerce, said the gulf crisis should "wake people up" to the need to balance environmental protections and economic costs.

"Imposing large costs on consumers and producers does have consequences that hurt people," Rahn said. "In tougher economic times, you have to be more prudent."

Whether industry succeeds in stalling environmental initiatives in Congress, the gulf crisis has already diverted the attention of lawmakers and the public.

Environmentalists had hoped the end of the Cold War would yield an environmental dividend, redefining national security in terms of planetary protections and shifting resources away from the military. Now they wonder if their hopes of beating swords into solar panels may be dashed by the exigencies of war.

"It's been interesting to see how quickly the debate has fallen back to the old frame of reference of Mideastern oil being the key to our energy future," said Worldwatch's Brown. "Only a few months ago, we were asking ourselves how can we phase out fossil fuels to save the climate."

"When you turn on the TV, it's like we're back in 1974," he said.

Murkowski's amendment would allow the president -- with congressional approval -- to lift prohibitions on oil development in sensitive areas during energy shortages.

"The United States is slipping inexorably into excessive dependence on foreign oil," Sen. Lloyd Bentsen (D-Tex.) said in support of the amendment. "The news of the last few days makes our vulnerability more evident and our response more urgent."

Similar efforts are underway to jump-start legislation to allow development of oil sites in the Arctic National Wildlife Refuge, a vast and unspoiled wilderness on Alaska's North Slope.

"If we're willing to risk American lives to protect a source of foreign imports, we certainly ought to be able to risk environmental consequences to develop" domestic sources, Sen. Ted Stevens (R-Alaska) said in an interview last week.

Although the administration has announced no plans to expand the limited offshore oil program unveiled a few weeks before the invasion, it is looking for ways to boost domestic production. Last week, Energy Secretary James D. Watkins asked California officials to expedite permits that would allow the $2.2 billion Point Arguello offshore project near Santa Barbara to begin shipping oil.

Congressional sources expect industry to use the Persian Gulf crisis to strengthen its last-ditch efforts to weaken clean air legislation now in a House-Senate conference.

The legislation is expected to cost industry at least $20 billion a year, costs that the Chamber of Commerce's Rahn said are unreasonable, especially in light of the gulf developments. He said the measures were drafted by "political whim" before the invasion and should be rewritten with a sharper eye to costs and benefits.

"These things are not a free lunch," he said.