Florida Gov. Ron DeSantis and former South Carolina Gov. Nikki Haley squared off tonight in the final debate before Monday’s Iowa caucuses. Haley dinged DeSantis over his past support for ending a federal ethanol mandate. DeSantis denied that he had in fact supported ending the mandate. It would be nice if at least one candidate onstage would support scrapping it.

DeSantis “should tell Iowans why he authored legislation to ban the Renewable Fuel Standard that’s so important to Iowans’ economy,” Haley declared. DeSantis retorted later that he did in fact support the Renewable Fuel Standard, offering as proof that “I’ve actually visited all 99 counties [in Iowa]. I’ve actually shown up to people’s farms, I’ve sat and I’ve listened to people about what they’re going through, how their economy is structured, and how it’s important that we’re producing energy here in the United States.”

Former President Donald Trump, who remains the favorite to recapture the Republican presidential nomination, did not participate in the debate. But he has previously criticized DeSantis on the same point, telling a Des Moines crowd in 2023 that “Ron DeSantis is aggressively pushing against ethanol, which I think would be devastating.”

In 2017, as a member of Congress, DeSantis did in fact co-sponsor H.R. 1314, the Renewable Fuel Standard Elimination Act. As the bill’s title implies, it intended “to repeal the renewable fuel program of the Environmental Protection Agency.”

The Renewable Fuel Standard is a federal program that requires “renewable fuel,” like ethanol derived from corn, to be mixed in with gasoline and diesel. The purpose, according to the Environmental Protection Agency, is “to reduce greenhouse gas emissions and expand the nation’s renewable fuels sector while reducing reliance on imported oil.”

In practice, though, ethanol is actually worse for the environment than traditional gasoline. And while ethanol is cheaper than gasoline, it also contains less energy by volume. Depending on the age of your vehicle, it can also be bad for your engine.

One thing ethanol is good for, though, is corn farmers. A 2021 report by Taxpayers for Common Sense called the Renewable Fuel Standard “the largest current subsidy for corn ethanol.” A 2022 study found, as Reuters put it, that “as a result of the mandate, corn cultivation grew 8.7% and expanded into 6.9 million additional acres of land between 2008 and 2016.”

It therefore makes perfect sense for two candidates desperate for votes in Iowa—the state that produces more corn than any other—to pledge fealty to a federal mandate that requires more people to buy corn-based ethanol. But just because something makes political sense doesn’t make it good policy.