In a joint statement released on Thursday, the White House, Department of Transportation, and the Environmental Protection Agency (EPA) announced that the Trump administration has ended negotiations with the California Air Resources Board (CARB) over vehicle fuel-efficiency standards. Until Thursday, the EPA, CARB, and the National Highway Traffic Safety Administration had been engaged in talks regarding the federal agencies’ decision to weaken emissions standards, which could result in two sets of limits – one for California and the dozen or so other states that use its regulations, and another for the rest of the country.

The Trump administration now plans to move forward with finalizing the Safer Affordable Fuel-Efficient Vehicles Rule (SAFE Vehicles Rule), which would freeze fuel-efficiency standards for vehicles at 2020 levels, undoing a regulation the Obama administration established to limit emissions supposedly contributing to climate change. Obama’s Corporate Average Fuel Economy (CAFÉ) standards would have required all cars and trucks to meet higher fuel efficiency standards by 2025.

The SAFE Vehicles Rule will almost certainly revoke the waiver the EPA previously issued to California which allows the state to set its own emissions standards. However, given that California’s independent regulatory authority to set its own more stringent standards for tailpipe emissions and fuel efficiency has been upheld by courts for the past half-century, the stage is likely set for an imminent legal battle.