Within months of Bush’s speech, the House and the Senate were reconciling a draft of a sprawling omnibus bill that would eventually be called the Energy Independence and Security Act, or EISA. In addition to requiring carmakers to improve fuel standards, a longtime priority for Democrats, the bill updated and expanded renewable-fuel standards, requiring fuel producers to mix in soy, palm and other kinds of vegetable oil with diesel fuel and to use ethanol from corn and sugar in gasoline. The bill also set tough standards for how much cleaner, in terms of carbon, each of those categories of fuel had to become — 50 percent for diesel, 20 percent for gas — and empowered the Environmental Protection Agency to judge what qualified.

The expected gains were enormous. The switch to biofuels, the E.P.A. would later calculate, promised to stop the release of 4.5 billion tons of carbon over three decades, the equivalent of parking every single American automobile for more than seven years. Before the bill passed in December 2007, Speaker Nancy Pelosi called it “the shot heard round the world for energy independence.”

The law had a profound effect. Biodiesel production in the United States would jump from 250 million gallons in 2006 to more than 1.5 billion gallons in 2016. Imports of biodiesel to the United States surged from near zero to more than 100 million gallons a month. As fuel markets snatched up every ounce of domestic soy oil to meet the American fuel mandate, the food industry also replaced the soy it had used with something cheaper and just as good: palm oil, largely from Malaysia and Indonesia, which are the sources of nearly 90 percent of the global supply.