California vs. Trump ‘will be a giant case’ over air rules

Gov. Jerry Brown at the State Capitol building in Sacramento in January 2017.

did not face “compelling extraordinary conditions,” compared to other states, in needing to reduce greenhouse gases, such as carbon dioxide. The state’s large population and geography contribute to serious smog problems, he said, but “when it comes to CO2 emissions, you know, California’s really in the same place as anyone else.”

The federal government could also argue that the 1975 statute that governs automobile efficiency – the Corporate Average Fuel Economy law – pre-empts California from setting its own fuel economy standards. Although California argues its rules are not fuel economy standards in word or practice, “they are very much related to fuel economy,” Holmstead said.

Sivas said the argument over federal pre-emption will likely be part of any

future court case, but is weaker than the legal theory that California does not face “extraordinary circumstances” is setting its own greenhouse gas rules.

“It’s an open question whether that provision (in the Clean Air Act) was intended to only deal with local pollution involving extraordinary conditions,” said Sivas, who was an attorney for Earth Justice, an environmental law firm. “It has never been fully litigated.”

Two cases at the U.S. District Court level – one in California, and one in Vermont – affirmed the authority of both states to regulate greenhouse gases. But neither of those cases was heard in U.S. appeals courts or the Supreme Court, meaning they are unlikely to have much bearing on any future Supreme Court deliberations.