Arnold Schwarzenegger, the Californian Governor, has withdrawn backing for an oil-drilling project off his state's coast.
The decision provides further evidence that the giant BP spill is shifting political debate in the United States on the wisdom of expanding offshore exploration fields.
"You turn on the television and see this enormous disaster, you say to yourself, 'Why would we want to take on that kind of risk?'" the Governor said, adding firmly, "It will not happen in California."
Mr Schwarzenegger had been pushing for approval of new drilling in the Tranquillon Ridge, off the southern California coast, which would have raised $1.8bn (£1.2bn) for the state over 14 years at a time when it is drowning in budget deficits. The money had been earmarked to maintain state parks.
It is another setback for the "Drill, baby, drill" lobby – the refrain championed in the 2008 presidential race notably by Sarah Palin – which vociferously argued that offshore drilling was safe and that it was the only way to help the US wean itself from dependence on foreign oil sources.
President Barack Obama disappointed environmentalists by agreeing to allow new drilling in coastal Atlantic areas and in eastern sections of the Gulf of Mexico. The White House now says that no new permits will be issued until the investigations into the BP rig spill are concluded.
Opponents of marine drilling, including some prominent US senators from coastal states, have mobilised to use the spill as ammunition to slow down or even block any expansion of offshore activity. They include Senator Bill Nelson of Florida, one of the states bracing for damage from the BP slick. Senator Nelson said that President Obama's plans for expanding off-shore drilling were "dead on arrival" in the US Congress. The extent to which Mr Obama changes his long-term stance may depend on how bad the spill becomes.
"This is exactly what they want, because now he can pander to the environmentalists and say, 'I'm gonna shut it down because it's too dangerous,'" Michael Brown, the former head of the Federal Emergency Management Agency under George Bush, complained. "This President has never supported Big Oil, he's never supported offshore drilling, and now he has an excuse to shut it back down."
A huge spill off the shores of Santa Barbara County in 1969 led to protests, a moratorium on new drilling and the launching of the annual Earth Day. Today there are 27 platforms siphoning oil from the seabed off California.