The next step is for the Senate to decide whether to approve the repeal. However, this process is complicated because the Senate parliamentarian recently ruled that the law used to overturn the rule—the Congressional Review Act—may not apply in this case. This law gives Congress the power to undo federal rules finalized in the last months of a president’s term, but its use here is under question.

The effort to overturn California’s authority comes as the Biden administration’s climate policies face opposition from Congress. California’s rules, which also impacted states like New York and Washington, aimed to cut vehicle emissions significantly by 2040. But opponents, including major automakers and industry groups, argue the rules could drive up vehicle costs and limit consumer choices. They also claim the rules are unrealistic given current supply chain and economic conditions.

Environmental advocates and some Democrats criticize the attempt to undo these standards, calling it a political move aimed at protecting fossil fuel industries. If the Senate rejects the repeal, the EPA will need to start a lengthy process to undo the rules through administrative channels, a process that could take years and leave California’s stricter standards in place longer.

Senator Shelley Moore Capito, a key supporter of the effort, said she’s working with colleagues to explore all options for reversing the California standards. The final outcome will depend on the Senate’s vote, but the move signals a heated debate over the future of clean vehicle policies in the U.S.