With the Iowa caucuses just two weeks off, would-be Democratic presidential candidates have each paid their obligatory tributes to corn ethanol.
The biofuel's intended uses for energy independence and greenhouse gas reduction have become matters of debate. But no one questions its political clout, economic importance or staying power, especially in the Midwest.
Virtually all politicians of all parties, whether they stand against climate change or for petrochemicals, must make the quadrennial pilgrimage to the throne of King Corn to succeed in the nation's first formal contest of the presidential-nominating season.
"Ethanol is not a green fuel," said Jason Hill, a professor of bioproducts and biosystems engineering at the University of Minnesota. "What ethanol really is, is another market for corn. [But] Iowa plays a disproportional role in American politics, and Iowa has corn. Any candidate against corn would be sunk in Iowa."
The same might be said in Minnesota. Iowa leads the nation in ethanol production. Minnesota ranks fourth, behind Nebraska and Illinois.
The influence of ethanol dates to 2005 and the passage of the federal law that established the Renewable Fuel Standard (RFS). The RFS dictates how many billions of gallons of biofuel-gasoline blends refiners must produce each year. Under the RFS, the number of bushels of corn used to make ethanol soared from 1.32 billion in 2004 to 5.6 billion in 2018.
"We convert one-third of corn grown in the U.S. to ethanol," Hill said. Still, "it offsets just 7 percent of gasoline use."
That was not how it was supposed to play out. The Energy Independence and Security Act of 2007, which succeeded the law that created the RFS, "set extraordinarily optimistic goals for future ethanol production," said David Swenson, an economist at Iowa State University who follows the ethanol industry. "We were at the peak of energy nationalism in the United States," and the country was increasingly dependent on foreign oil. The idea was to produce more domestic energy. "Then all of sudden we had the shale oil revolution, and everything changed."