President Trump has repeatedly promised to end what he terms the “Biden electric vehicle mandate.” In a day-one executive order, Trump directed that this EV mandate should end. This action was only the beginning, not the end, of rolling back the Biden administration’s de facto EV mandate. In order to end this mandate, three major regulatory actions must be revised or rejected: the tailpipe emissions standards from the Environmental Protection Agency (EPA), the Corporate Average Fuel Economy standards from EPA and the Department of Transportation (DoT), and the state of California’s Advanced Clean Cars II regulation, granted a waiver from Clean Air Act preemption during Biden’s lame duck period. Of these three prongs, the California program subject to the waiver is the most important as it takes actions (such as banning internal combustion vehicles) that no federal agency has been granted the power to take, and because both the tailpipe mandate and the CAFE mandate rely on the California regulation for legal support.

While none of these three prongs alone constitute an electric vehicle mandate, the interaction of all three creates a de facto EV mandate by attempting to regulate non-battery-electric vehicles out of the market. The tailpipe emissions standards from EPA do this by setting emissions standards so low that only full battery-electric vehicles can qualify; not even highly efficient hybrids can meet the tailpipe mandate. The CAFE mandate does this by setting fleetwide fuel efficiency requirements so high that as many as two-thirds of the cars automakers manufacture will have to be electric.

California’s program is not restricted to California.  Under the Clean Air Act, if California receives a waiver, other states can follow California’s regulations, and indeed, many have. In fact, thus far, 18 states have followed some parts of California’s EV mandate. California has also used this provision to bully car manufacturers into following and defending California’s regulations.

If both of these federal mandates sound excessive and unreasonable, that’s because they are. Both the tailpipe and CAFE regulations likely exceed the agencies’ statutory authority. Neither EPA nor DoT has the authority to mandate EVs, which is why these standards are presented as technology-neutral. These agencies also have requirements about technological feasibility and compliance costs that must be part of their regulatory considerations. Both these regulations face strong legal challenges, though the Trump administration is also moving to review and replace the regulations.

The major regulatory defense offered by EPA and DoT to their excessive mandates is to rely on the third prong, California’s ACC II program, the main feature of which is a ban on the sale of internal combustion engines. The agencies assume that this regulation takes effect, so California and the more than a dozen states who choose to follow their regulations all mandate electric vehicles. With these mandates already in place forcing the adoption of EVs, the federal agencies claim that the cost and feasibility of compliance with their mandates will be small because automakers and the public will already be forced to reach those levels by the state mandates.

So, while there are indeed three components to the “Biden EV mandate,” the California waiver program is the foundation upon which it all stands. The only way that the tailpipe and CAFE mandates are even remotely defensible is if California’s EV mandate is in effect. The Biden administration didn’t have the power to mandate EVs directly, but by waiving California’s program, they could achieve the same result through the back door.

All this means that the key element that must be tackled to end the Biden de facto EV mandate is the revocation or rejection of the waiver for the California EV mandate. There is a potential regulatory process for withdrawing a waiver that has already been granted, though there are legal questions surrounding that process, and it would take an extended period to get through administrative procedure hurdles. Congressional action to disapprove of the granting of the waiver through the Congressional Review Act process, however, would immediately halt the implementation of the California program and thus fatally undermine the entire structure of the Biden EV mandate. Either way, the only way to end the Biden EV mandate is to revoke California’s waiver.