In a major environmental victory for California and 16 other states, a federal court in Fresno on Wednesday upheld a bid to slash auto emissions to combat global warming, a move fiercely opposed by automakers and the Bush administration.

The fight now shifts to Washington.

A Senate vote might come as soon as today on an energy bill that says cars and trucks must meet a fleet fuel-economy average of 35 miles per gallon by 2020. That's compared with 27.5 mpg for cars and 22.2 mpg for trucks today. The House approved the fuel-mileage increase last week.

Wednesday's ruling that California has the authority to impose greenhouse-gas-emission-related mileage standards on cars and trucks - a plan that would cut emissions from vehicles 30 percent by 2016 - increases pressure on the U.S. Environmental Protection Agency to give the state a waiver to do that.

The state requested a waiver in late 2005, and California Attorney General Jerry Brown sued the EPA in November over its two-year refusal to say yes or no. The agency has said it will issue a decision on California's waiver by year's end.

Wednesday's 57-page opinion by U.S. District Judge Anthony Ishii follows three other court losses this year by the auto industry and the administration.

Ishii's ruling and a similar decision by a federal judge in Vermont three months ago stem from a major Supreme Court ruling in April that the EPA has authority to regulate greenhouse-gas emissions under the Clean Air Act - and can grant waivers to California to enforce its own regulations.