In coming weeks the remaining presidential candidates will be trying to outshine each other in the Golden State.

While they are here, all should be pressed to answer a simple yes or no question: Will they allow California to implement its 2002 law limiting emissions of greenhouse gases from cars and trucks sold in this state?

To date, the courts have upheld California's authority to set such limits, and 19 other states have moved to adopt similar standards. But after extensive lobbying by the auto industry, the Bush administration in December denied California the waiver it needed to implement its 2002 law. That has prompted California and other states to sue the U.S. Environmental Protection Agency over its legal reasoning in denying the waiver.

Barring quick action by the courts, the next president of the United States will be the ultimate decider on the clean cars law, which effectively would become the national standard. Under the law, automakers would be required to achieve a 30 percent reduction in carbon dioxide and other gases emitted from their vehicle fleets by 2016.

To see where the candidates stand on this issue, this page queried the 10 leading presidential candidates, and asked them whether they would uphold or reject the EPA action.

On the Democratic side, former North Carolina Sen. John Edwards was the first to answer, saying "the EPA has a legal and moral responsibility to allow the states to do their part to help stop global warming. …When I am president, the EPA will get out of the way."

Sen. Barack Obama also said he would overturn the EPA's decision, calling it "yet another example of how this administration has put corporate interests ahead of the public interest."

Sen. Hillary Clinton didn't respond, although during a Jan. 11 visit to California she said she supports "what the state is trying to do to begin to regulate the fuel pipe emissions."

So far, none of the Republican candidates has staked out a clear position on California's law, although it is possible to guess where at least some of them stand.

While campaigning in Michigan, former Gov. Mitt Romney lashed Sen. John McCain for supporting stronger fuel economy standards, saying they would devastate Michigan's economy.

Other GOP candidates – including former New York Mayor Rudy Giuliani and Rep. Ron Paul of Texas – oppose tougher fuel economy standards. Aside from McCain on the GOP side, only Mike Huckabee has voiced his support for improved fuel efficiency.

So far, the threat of global warming has been largely overlooked in the presidential campaign. As Gov. Arnold Schwarzenegger told The Bee's editorial page last week, it is "one of the issues that has not been addressed enough" by the candidates.

That needs to change in the days ahead, as the Feb. 5 primary in California becomes an increasingly valuable prize for top contenders.

Schwarzenegger himself could play a role. Last year, he briefly entertained plans to hold a candidates' forum on climate change and energy policy. He should revisit that idea. All the top contenders should be held accountable for their environmental positions, or their refusal to take seriously issues of concern in California.