California governor plans to veto environmental rules bill California Gov. Gavin Newsom announced Saturday he will buck Democratic legislative leaders by vetoing legislation aimed at stopping the Trump administration from weakening oversight of longstanding federal environmental laws in California

SACRAMENTO, Calif. -- California Gov. Gavin Newsom announced Saturday he will buck Democratic legislative leaders by vetoing legislation aimed at stopping the Trump administration from weakening oversight of longstanding federal environmental laws in California.

His announcement came less than a day after lawmakers approved the bill on the chaotic final day of the year's legislative session.

Newsom said in a statement he fully supports the aims of the bill but argued it wouldn't give California new authority to push back on the Trump administration. He also said it would stop California from relying on the best available science. His office further said he's concerned about a piece of the bill that could require the state to rely on Endangered Species Act opinions written roughly a decade ago.

Despite his pledge to veto the bill, Newsom was quick to praise Senate President Pro Tempore Toni Atkins, the bill's author and an important ally for the freshman governor.

"I look forward to my continued partnership with Senate President Pro Tempore Toni Atkins - who is an extraordinary leader on the environment and for our state at large - to ensure California can continue to protect our environment and our workers against federal rollbacks, and push back against Trump's anti-environment agenda," he said in a statement.

Atkins, though, said she's "strongly disappointed" in Newsom's decision, and she disputed his characterization of the bill. It allowed state agencies to use the best scientific evidence available and gave the state authority to "backstop baseline standards" if the federal government rolled them back, she said in a statement.

In opposing the bill, Newsom is siding with the state's water contractors and Democratic U.S. Sen. Dianne Feinstein.

"We can't really have a California system and a federal system," said Jeffrey Kightlinger, general manager of the Metropolitan Water District of Southern California, which delivers water to nearly 19 million people. "We're all in the same country here, so we need to find a way to make this work."

California has a history of blunting Republican efforts at the federal level to roll back environmental protections. In 2003, shortly after the George W. Bush administration lowered federal Clean Air Act standards, the Legislature passed a law banning California air quality management districts from revising rules and regulations to match.

More recently, after the Trump administration announced plans to roll back auto mileage and emission standards, Newsom used the state's regulatory authority to broker a deal with four major automakers to toughen the standards anyway.

State lawmakers tried this last year, but a similar proposal failed to pass the state Assembly. But advocates say several recent announcements by the Trump administration — including plans to weaken application of the federal Endangered Species Act — have strengthened support for the bill.

The bill could have played out most prominently in the management of the state's water, which mostly comes from snowmelt and rain that rushes through a complex system of aqueducts to provide drinking water for nearly 40 million people and irrigation to the state's $20 billion agricultural industry.

It aimed to make it easier for state regulators to add animals protected under California's Endangered Species Act — animals that have historically been protected under federal law. It would then apply the state's Endangered Species Act to the Central Valley Project, a federally operated system of aqueducts and reservoirs that control flooding and supply irrigation to farmers.

But it's not clear if a state law would apply to a federal project, "which could generate years of litigation and uncertainty over which environmental standards apply," according to a letter by Feinstein and four members of the state's Democratic congressional delegation.