Donald Trump didn’t forget he promised Iowa’s corn growers he’d be there for them if they helped send him to Washington. He’s told the U.S. Environmental Protection Agency to start the process of permitting the sale of E15 — a gasoline blend that’s 15 percent ethanol — year-round.

Increasing demand for corn-based ethanol is the exact opposite of what should be done. It constitutes a massive handout to special interest groups and E15 imposes serious costs on the average American family while providing virtually zero environmental benefit.

The Renewable Fuel Standard, which dictates that a defined percentage of biofuels be blended into the gasoline supply already funnels some E15 into our tanks.

The fact that technological advances in biofuel production didn’t materialize meant, under the RFS, an even heavier reliance on ethanol. That’s cost Americans dearly at the pump, and in everyday life — as anyone who forgot to drain fuel out of their lawnmower knows.

Ethanol production consumed 40 percent of all corn harvested in 2014. This has driven up the price of anything made from corn or which has corn in its food chain. The wholesale prices of corn-fed beef, pork, and chicken have increased by at least 200 percent since the RFS was adopted.

That reverberates down through the distribution chain, driving up food costs for consumers and businesses alike. Chain restaurants have watched their food expenses go up by over $3 billion.

Gasoline with high ethanol content is also incompatible with most American cars. The engines and fuel systems in three out of four cars aren’t made to run on E15. And automakers are warning that E15 could even invalidate car warranties.

“Ford does not support the introduction of E15 into the marketplace for the legacy fleet…Fuel not approved in the owner’s manual is considered misfueling and any damage resulting from misfueling is not covered by the warranty,” the automaker told the EPA.

Congress initially imposed ethanol requirements to curb our nation’s reliance on foreign oil and to reduce greenhouse gas emissions. Ironically, these problems have largely been solved — not by ethanol, but by the oil and natural gas sector.

Our reliance on oil imports has been curbed. The United States now produces more petroleum and natural gas than any other country.

And since 2009, American crude production has spiked almost 80 percent and we’re once again a net exporter.

Up until 2018, American carbon emissions had significantly fallen, thanks to the rapid expansion of domestic natural gas production. Its widespread adoption has cut energy-related emissions to their lowest level in 25 years. The addition of ethanol and biodiesel to the fuel supply have almost nothing to do with it.

Ethanol production has huge environmental costs that far outweigh its paltry emissions benefits. According to a study in the American Journal of Agricultural Economics, companies have been digging up once-pristine prairie habitats and converting them into corn fields to meet ethanol production targets. The United Nations has warned that such conversions “pose risks to ecosystems and biodiversity.”

Secretary of Agriculture Sonny Perdue, a key player in this debate, says President Trump’s attitude toward year-round E15 sales has always been “let’s get this done.” We’ll all be the better if we don’t.