WASHINGTON – The Gulf oil spill has triggered a crisis of confidence, shaking Americans’ views about BP, the oil industry, technology and President Obama and slowing a planned expansion of domestic offshore oil drilling.

Are the worst spill in U.S. history and images of dead birds and toxic syrup lapping at Gulf shores shocking enough to be a tipping point for energy policy and consumer behavior, however?

Will Americans rush to smaller cars or spend more to buy hybrids? Will politicians embrace gas taxes and charges on large carbon polluters or adopt other measures to punish fossil-fuel burning and encourage alternative energy use?

Public willingness to change — and the political courage to provoke change — may hinge on how long the spill continues, how the wind blows, how the cleanup goes and the extent of damage to wildlife, seafood, jobs, tourism and real estate.

The debate also comes as the nation is emerging from the worst economic crisis in decades, saddled with debt, trying to wrap up two wars and embarking on an experiment in health care that has left many Americans unsettled and businesses bracing for higher taxes. It also comes as key developing nations, including China and India, rely heavily on oil and coal to drive their expansions.

For now, many experts say Americans aren’t ready to change.

“I don’t think it’s a game-changer,” said Antoine Halff, the head of commodities research at Newedge, a New York-based brokerage firm. “It drives home the risky nature of meeting the demand for oil,” but he predicted perspective largely would be offset by a more powerful reflex: “People like to have their cake and eat it, too.”

Even the most cautious analysts expect the crisis to lead Americans to embrace greater government regulation of offshore drilling and perhaps to expedite higher fuel-efficiency standards for cars and trucks.

Advocates of a faster transition from an oil economy to alternative energy are seizing the opportunity to push for as much as they can get.

“Perhaps in the face of this terrible crisis we can find the political will and the political leadership to get it done,” said Kevin Knobloch, president of the Union of Concerned Scientists. The National Resources Defense Council Action Fund has launched ads in eight states pressuring senators to pursue a “strong clean-energy climate bill.”

The searing images of the spill already are having some impact. In a USA Today/Gallup poll released last week, 55 percent of those polled said environmental protection should be prioritized, even if it meant limiting U.S. energy production.

In the same poll, however, 50 percent said they still supported increased offshore drilling, perhaps realizing the nation depends so heavily on oil that change will be difficult.

The lion’s share of the oil used domestically goes to power cars, trucks and airplanes, and alternatives such as hybrid-powered engines remain too costly and inefficient for most Americans.

“We’ve been through this sort of drill before with the oil embargo back in the 1970s, the various oil price shocks,” said Frank Felder, director of the Center for Energy, Economic and Environmental Policy at Rutgers University in New Jersey. “Everyone gets riled up and then we go back to our ways. The reason we do it is that oil is just very, very useful.”

With the economy recovering gingerly and elections looming in November, politicians aren’t radically changing their rhetoric, either.

Obama has said while the Gulf spill should be “a wake-up call” for the need to invest in renewable energy, he continues to support expanded domestic drilling as part of a national security effort to make the country less dependent on foreign oil.

Sen. John Kerry, D-Mass., the leading author of the major energy bill the Senate is considering this year, last week said: “The sooner we can move off fossil fuels and to a new energy paradigm, the better for our nation.” At the same time, he said, “We’re not going to stop drilling in the Gulf. Let’s be realistic.”

“About 30 percent of our transportation fuel comes from the Gulf,” Kerry said. “You think Americans are suddenly going to stop driving to work tomorrow? You think people are going to stop driving trucks to deliver the goods to the department store? It’s not going to happen.”

Some say the challenges are overstated and that Americans can end their oil dependence with a few small lifestyle changes: promoting electric vehicles, investing in light rail, creating pedestrian- and bike-friendly communities and exploiting alternatives such as natural gas.

“Meeting this challenge will not be easy, but nor will it require tremendous sacrifices,” the American Security Project, a nonpartisan research center, and the Sierra Club, a leading environmental group, wrote in a report last week. “There is a powerful economic rationale for taking action now.”

Sean Kay, chairman of the international studies program at Ohio Wesleyan University, said even if the spill made Americans rethink how they used oil, it would take “a sustained campaign” by politicians, lasting years and with far more intensity than on display now, to shift behavior and spending.

Kay said expanding alternative energy was essential, but Americans still consider the short-term costs more important than the long-term benefits.

The 1989 Exxon Valdez spill didn’t stop Americans from driving, but it did force oil companies to adopt double-hulled tankers, said James Sweeney, a management science and engineering professor who heads Stanford University’s Precourt Energy Efficiency Center. In the same way, many experts said, the Gulf spill probably will lead to tougher government regulations on offshore drilling.