The best that can be said about new vehicle fuel economy rules issued by federal regulators last week is that the largest sport utility vehicles will finally have to meet gas mileage standards, no matter how meager. On the bad side, buried in the voluminous rules is language barring states from enacting rules to limit greenhouse gas emissions from tailpipes, which would cut pollution that contributes to climate change while also improving fuel economy.

Fortunately, Maine’s senators and others aren’t simply going along with this twisted logic that would prevent states from reducing pollution when the federal government has refused to do so.

Maine is among 10 states that have followed California in adopting rules to limit car pollution that is linked to climate change. In 1993, Maine joined with other New England states in adopting California’s Low Emission Vehicle program, which set stricter standards for vehicle emissions than the federal government. Last year, the Maine Board of Environmental Protection approved rules that, for the first time, require emissions reductions among all cars on the road, not just small classes of cars. By 2012, tailpipe emissions of greenhouse gases will have to be reduced by 22 percent compared with the 2002 fleet.

These rules could be undone. California needs a waiver from the U.S. Environmental Protection Agency to finalize the greenhouse gas rules. The Clean Air Act allows for such waivers, which the agency has granted to California more than 40 times in the last 30 years.

The language buried in the preamble to the fuel economy rule says that regulations of carbon dioxide emissions from motor vehicles are pre-empted. Although the language is not binding, judges can refer to it as precedent (conveniently, automakers are currently engaged in a court battle to kill the California standards). It also sends the message that the Bush administration is not going to grant California’s waiver.

Twenty-one senators, including Olympia Snowe and Susan Collins, have already sent a letter to EPA Administrator Stephen Johnson, urging that the waiver be granted. Denying the waiver would be “disastrous to the public who support the actions of their governments to protect their health and safety,” Sen. Snowe said.

While not commenting specifically on the climate change tailpipe emissions, a National Academy of Sciences panel last month said that California’s tougher rules had been beneficial because the state is a “proving ground for new emissions-control technologies that benefit California and the rest of the nation.” The panel said California’s waivers should continue.

As for the substance of the rules, the new mileage standards would, for the first time, set minimum requirements for the largest sport utility vehicles, although large passenger trucks would remain exempt. Big SUVs, like Hummers, would have to increase their fuel economy to 24 miles per gallon by 2011. The Bush administration says this would save 10.7 billion gallons of gasoline over the life of these vehicles. U.S. consumers use that much gas in a month, so the savings are minuscule.

The rule itself won’t make a dent in America’s dependence on foreign oil. Worse, the language about emissions is a troubling warning of the Bush administration’s commitment to do nothing about climate change. Congress should follow the lead of Sens. Snowe and Collins and address both problems.