EDITORIAL SUE AWAY STATE CAN LEAD WAY ON GREENHOUSE GASES.

CAN California win permission to make its own rules on cutting back greenhouse-gas emissions from cars? The state is going to sue and sue and sue again until we get it, says Gov. Arnold Schwarzenegger.

To that bravado, Californians should say bravo.

The target of the state's lawsuit, the Environmental Protection Agency, doesn't have much of a case. The U.S. Supreme Court has already ruled that carbon dioxide and other greenhouse gases are pollutants, and California has already won permission many times to make state regulations tougher than federal regulations.

Schwarzenegger said last week that he is tired of waiting for a response from the EPA to requests two years ago for a waiver allowing the state to crack down on carbon dioxide, which can add to the greenhouse effect.

The EPA says it will come up with a response by the end of the year, in which case California's lawsuit could be rendered moot. But the state's action could force Washington to be true to its word.

The EPA is on the spot. The Bush administration has opposed federal regulations on greenhouse gases, yet 14 states have passed regulations similar to California's and will likely join the state's suit.

Once successful, this group will leave the federal government behind and set the national agenda for global warming. California and the 14 states make up 40 percent of the U.S. population.

California's tailpipe regulations go back to 2002, and they are a central part of Schwarzenegger's global-warming legislation. When implemented, the rules would cut carbon emissions by one-fourth over the next 12 years.

What do carmakers say? They've learned from the days in which they fought ineffectually against catalytic converters and almost every improvement in auto emissions. Now they say they want to be part of the solution, and support federal legislation that would increase fuel economy up to 40 percent by 2022.

They just don't like the idea of rules being different from one state to the next. And that's a good point, but nearly half the nation's population is going in the other direction now, and carmakers need to figure out how to travel the same road.

It's not clear whether any of these regulations would make enough difference to avert climate change. We might be in the middle of an inevitable cycle of warming that could last thousands of years.

But that's not an argument to do nothing. Society only stands to benefit from finding more efficient ways to generate energy. In the long term, those efficiencies will translate into cleaner air and economic savings.

So sue away, Governor. The EPA is on the wrong side of this argument.