Transportation is the largest source of greenhouse gas emissions in America, and the majority of it comes from cars and small trucks. That’s a major reason why President Barack Obama, in 2012, introduced a rule requiring automobile manufacturers to make their vehicles more fuel efficient—from 37 miles per gallon to more than 51 miles by the year 2025. As a side benefit, drivers would save money on gas and America’s oil reserves would last longer, reducing the incentive for energy companies to extract more of it.

But now President Donald Trump wants to “Make Cars Great Again”—by letting them remain as dirty as they are now. In an op-ed with that title in Thursday’s Wall Street Journal, the Environmental Protection Agency’s new chief, Andrew Wheeler, and Transportation Secretary Elaine Chao announced a proposal to end those Obama-era requirements. Freezing fuel-efficiency standards, Chao and Wheeler wrote, will benefit consumers by giving them “greater access to safer, more affordable vehicles.”

This claim is based on specious evidence, experts say. In truth, the administration has concocted a tortured, flimsy argument—that cleaner cars will cost thousands more, and kill thousands more people—to scare Americans into believing that the government should scrap its most consequential policy for reducing emissions.

The administration’s 978-page proposal is called the SAFE Vehicles Rule—SAFE being an acronym for “Safer Affordable Fuel-Efficient”—and it argues that cleaner vehicles are more dangerous than dirtier ones. “Today’s proposed rule is anticipated to prevent more than 12,700 on-road fatalities and significantly more injuries as compared to the standards set forth in the 2012 rule,” it states. It’s not entirely clear where that statistic comes from, but as Brad Plumer explained in The New York Times, it’s based on three arguments:

First, people who buy fuel-efficient vehicles will end up driving more, increasing the odds that they will get into a crash. Second, the fuel-efficient vehicles will themselves be more expensive, slowing the rate at which people buy newer vehicles with advanced safety features. Third, automakers will have to make their cars lighter in response to rising standards, slightly hurting safety.

Dirty cars, in other words, are heavier—and when heavy cars get into accidents, the people inside them are less likely to die. Thus, the administration argues, “It is now recognized that as the stringency of [fuel efficiency] standards increases, so does the likelihood that higher stringency will increase on-road fatalities. As it turns out, there is no such thing as a free lunch.”