President Trump's EPA has just fallen off the wagon. Or, perhaps, it was thrown off.

Under White House orders, the agency has abandoned plans to reduce the amount of ethanol that must, under the mandate known as the Renewable Fuel Standard, be mixed into the gasoline supply.

This is because Iowa's two Republican senators flexed their muscles in a closed-door meeting with EPA Administrator Scott Pruitt, and he caved. Sens. Chuck Grassley and Joni Ernst threatened to block confirmation of four of Trump's nominees to the agency, including the appointee who would preside over enforcing the RFS. Republican governors from the Midwest reportedly got in on the act as well, twisting Trump's arm.

Ideally, drivers would simply buy whatever amount of ethanol they actually wanted, including none. There wouldn't be a special government requirement to use a minimum amount. Unfortunately, contrary to the deceptions peddled by the ethanol industry, the very existence of the RFS demonstrates conclusively that this product is being forced on unwilling consumers.

The driving public is stuck with the RFS. Since the RFS was established in last decade's energy bill, it has become clear that absent huge changes in the country's fuel infrastructure, the economy is simply incapable of consuming the amounts of ethanol that the feds order it to buy.

America uses 140 billion gallons of liquid fuels each year. Thus, it will not be able to consume 36 billion gallons of ethanol by 2022, as the RFS requires on paper, unless ethanol is mixed into the fuel supply in concentrations far too high for many existing engines and the supply infrastructure.

Yet refiners face heavy penalties if they don't do their part to sell the required volume of biofuels. Right now, smaller refiners are being harmed badly by compliance costs.

You may wonder why anyone should sympathize with refiners. But you don't have to. You can simply consider the program's supposed benefits and recognize them for the fiction they are. Ethanol doesn't reduce carbon emissions, it increases smog, and it cuts gas mileage. The entire scientific basis on which the RFS was based on is a hoax, disavowed by the environmentalist Left as much as by the free-market Right.

In short, there aren't arguments for the RFS, just weak excuses, pleaded by the people who profit from it.

The notion of ethanol as a political powerhouse was crushed by Texas Republican Sen. Ted Cruz's victory in the 2016 Iowa caucuses. Cruz won in Iowa despite campaigning to phase out RFS over five years.

If Cruz can do that, so can other Republicans running for president, and Democrats too, for that matter. Here's hoping a few of them figure it out quickly.