Federal and state governments, through subsidies and mandates, push the agriculture and energy industries to grow corn for burning in car engines, and this has many political, economic and environmental downsides.

Here's another: "A University of Wisconsin-Madison study showed that millions of acres of wildlife habitat nationwide have been converted to crop production — most of it planted with corn for ethanol."

Specifically, the study found: "Aggregated across the U.S. ethanol sector, the four-year conversion rate of arable non-cropland to cropland was highest within 25 miles of refineries ..."

In short, grasslands and prairie were twice as likely to be converted to farm fields if they were close to ethanol refineries. Grasslands are crucial habitats for animals from bison to ferrets to meadowlarks.

The major driver of U.S. ethanol production is the federal ethanol mandate (known as the Renewable Fuel Standard), which candidate Donald Trump supported while trying to win the Iowa caucuses, but on which he has been cagey since the election.

Timothy P. Carney, the Washington Examiner's commentary editor, can be contacted at tcarney@washingtonexaminer.com. His column appears Tuesday nights on washingtonexaminer.com.