The Trump EPA’s latest proposal, however, demonstrates that this new brand of cooperative federalism comes with a huge caveat: Cooperative federalism is the goal unless a state or local government wants to go above and beyond federal standards to protect the local environment and public health.

Last week, Wheeler and Heidi King, head of the National Highway Traffic Safety Administration, announced a proposal to freeze automobile fuel economy and greenhouse gas emissions standards at 2020 levels, rather than requiring them to slowly escalate over time to deliver more efficient vehicles to customers. As a result, Americans will consume more foreign oil, pay more at the gasoline pump, and breathe dirtier air.

But the EPA didn’t stop there. Wheeler also proposed to eliminate states’ long-standing authority to set stronger limits on vehicle tailpipe pollution.

The Clean Air Act allows California—given its uniquely severe and intractable air pollution problems—to set vehicle emissions standards that are more stringent than the federal standards. To do this, the EPA must authorize the state (issue a “waiver,” in legal parlance) to set its own vehicle emissions standards, unless it can show that California does not face “compelling and extraordinary conditions.” For almost 50 years, Democratic and Republican administrations have continually recognized California’s air quality challenges and issued waivers.

Another provision of the Clean Air Act allows other states to opt in to California’s vehicle emissions standards. So far, 12 other states have chosen to implement California’s standards, rather than those set by EPA.

Wheeler’s decision to revoke California’s waiver sets the stage for a nasty legal battle between the EPA and states—the very antithesis of cooperative federalism. Back in 2010 and again in 2012, California struck an unprecedented deal with the Obama administration and automakers to harmonize the state’s standards with federal standards, hitting a fleet-wide goal of 54.5 miles per gallon by 2025. For their part in the negotiations, automakers were rewarded with certainty: being able to plan their fleets around one national standard.

The Trump administration’s proposal to freeze and weaken the one national standard reneges on that deal. California and the 12 other states now have two choices: Accept the frozen standard and the additional air pollution that comes with it or fight the Trump administration in court.

Attorneys general from 19 states and the District of Columbia have promised to sue if the EPA finalizes the proposal to strip states of their authority to set stronger pollution standards for vehicles. Pennsylvania Attorney General Josh Shapiro called last week’s proposal “insane” and reminded the Trump administration of its duty to “protect my state’s rights and interests and the environmental rights of all Pennsylvanians.”

The auto industry responded to the Trump administration’s announcement with a call for “substantive negotiations” with California. For automakers, a long, protracted legal battle with state attorneys general creates uncertainty and regulatory limbo—a nightmare scenario for companies that need to design and plan their fleets years in advance. In a statement, the Auto Alliance urged the Trump administration to find a compromise solution with the states that “sets continued increases in vehicle efficiency standards”—a direct repudiation of the Trump administration’s preferred approach of freezing standards indefinitely.

If the automobile industry isn’t on board, the question is: Who is? The answer likely will surprise no one: the oil industry. The major oil companies have kept a low profile in this fight, choosing to quietly lobby the Trump administration behind closed doors rather than launching a public push. But their spoils are clear. Americans would burn 500,000 more barrels of oil every single day by the early 2030s as a result of the fuel economy freeze.

The Trump EPA came in promising to usher in a new era of so-called cooperative federalism. For his part, President Donald Trump stood side by side with automaker CEOs in March 2017 and promised to support them. But with this new proposal to freeze federal vehicle efficiency standards, the Trump administration is throwing states’ rights, auto workers, and consumers—both principle and people—under the bus to benefit the oil industry.

Alison Cassady is the managing director of Energy and Environment Policy at the Center for American Progress.