Perversely, the most enduring consequence of the 1970s belief that energy supplies were running out was not to use less, but to look for more. In this quest, Jimmy Carter, arguably the most ecologically minded president in U.S. history, endorsed policies that today seem like environmental folly. Notably, his administration sought to offset the approaching decline of oil and gas by tripling the use of coal, a much dirtier fuel. Just as peak oil had provided justification for foreign-policy misadventures in the 1920s and 1930s, it proved a friend to Big Coal in the 1970s and 1980s. Meanwhile, oil firms found so much crude that by the end of the 1990s real prices had fallen to half--sometimes a fifth--of what they were during Carter's day.