A federal judge in San Francisco on Monday poked a gaping hole in California's bid to make the auto industry pay for any contributions it makes to global warming.

In a 24-page ruling, U.S. District Judge Martin Jenkins dismissed the state's lawsuit against six automakers, concluding that the federal courts are not the place to resolve the complex issues surrounding global warming. The judge said it is up to Congress and the executive branch to address California's arguments, not judges.

The ruling is a major setback for Attorney General Jerry Brown, who has made global warming one of his cornerstone issues since he was elected last year. Even though Brown inherited the global warming lawsuit from his predecessor, Bill Lockyer, he pressed ahead with the controversial case when he took office.

California is the only state to sue the auto industry for damages over global warming, arguing that the "Big Six" automakers violate the state's public nuisance laws because their vehicles emit greenhouse gases. General Motors, Ford, Chrysler, Toyota, Honda and Nissan were named in the lawsuit, which argues that they contribute to a range of environmental problems, including the decline of the Sierra snowpack and threats to wildlife.

The lawsuit sought unspecified money damages.

Deputy Attorney General Ken Alex, who argued the case for Brown, said he was "disappointed" in the ruling. His office is reviewing whether to appeal it to the 9th U.S. Circuit Court of Appeals.

"We're not totally surprised a district court wouldn't want to jump in with both feet into a global warming matter," Alex said.

Theodore Boutrous Jr., the lead lawyer for the automakers, called Jenkins' ruling "absolutely correct." Michigan backed the auto industry in the case.

"We have said all along that global warming presents exceedingly complex policy issues that must be addressed at the national and international levels by Congress and the president, not the federal courts," Boutrous said.

Jenkins, in siding with the industry's arguments, found that a lawsuit was a flawed way to deal with the global warming issue because it collided with the federal government's role in environmental regulation, as well as the Bush administration's foreign policy on regulating greenhouse gases.

But Jenkins' primary concern was the difficulty of sorting through what he called "a thicket" of issues that are best left to the political and scientific arena. In the ruling, Jenkins pointed out that the federal courts are ill-equipped to evaluate how much of a factor auto emissions may be in global warming.

"The court is left without guidance in determining what is an unreasonable contribution to the sum of carbon dioxide in the earth's atmosphere," the judge said, " or in determining who should bear the costs associated with global climate change."

The auto industry is also squaring off with California in the courts in a separate case. That case takes a different legal tack, challenging a state law requiring the automakers to reduce vehicle carbon emissions by 2009. A federal judge in Vermont last week rejected the industry's challenge to that state's nearly identical law, boosting California's hopes of prevailing in the courts here.

Gov. Arnold Schwarzenegger also has threatened to sue the federal Environmental Protection Agency if it doesn't grant a waiver to its rules by October allowing the state to set its own emissions standards for cars and trucks sold here.