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Why it’s important: California environmental regulators are no strangers to legal threats from industry groups. But recent Supreme Court cases that have limited the EPA’s ability to protect wetlands and regulate greenhouse gases have climate leaders concerned that state-of-the-art environmental rules California could be next.

On these cases: Judges have a number of tools to overturn EPA approvals. One is the major issues doctrine, which prohibits agencies from resolving issues of “great economic and political importance” without clear authorization from Congress. Another example is the recent reversal of Chevron deference, which reduces the power of federal agencies to interpret ambiguous language in laws.

The Californian strategy: California government lawyers are targeting conventional pollution, rather than just greenhouse gases, for which the Supreme Court has been more skeptical about the use of the Clean Air Act. The state has also made progress in getting automakers like Ford, Volkswagen and Honda to follow California’s tailpipe emissions rule, regardless of election and legal outcomes.

Industry refusal: Groups representing trucking fleets and the rail industry have filed more than a half-dozen lawsuits challenging California’s zero-emission vehicle rules, arguing they violate interstate commerce rules regulated by Congress and would result in the bankruptcy of small operators. These industries have shown no interest in making deals.

To learn more, read the full article on POLITICO and in POLITICO’s California Climate newsletter.

This story is published in partnership with POLITICO.