The Supreme Court declined Monday to take up an appeal from conservative states challenging California’s ability to establish strict vehicle emission rules that effectively set the standard for the rest of the nation.

The Supreme Court says it will take up a business-backed appeal that could make it easier to challenge federal regulations, acting in a dispute related to California’s nation-leading standards for vehicle emissions.

Stepping into a legal fight that has been raging for years, the Supreme Court said it would decide whether California can set its own, often strict vehicle emissions standards that include curbs on greenhouse gases.