Des Moines Register: Iowa ethanol and biodiesel producers warned President Donald Trump on Friday that imposing restrictions on biofuels production “would be viewed as a declaration of war on rural America.” The Iowa Renewable Fuels Association asked Sens. Chuck Grassley and Joni Ernst to tell Trump that limiting biofuel production would be a “complete abdication of his repeated promises” to protect the Renewable Fuel Standard, a federal law that mandates a minimum volume of biofuels to be mixed in the nation’s gasoline and diesel fuel supply.