In terms of its effect on the lives of Americans, as well as the economy, the change of U.S. policy announced by the Trump administration last month to almost no media attention is a big deal. Ellen Knickmeyer of the Associated Press picked up on it belatedly: Conserving oil is no longer an economic imperative for the U.S., the Trump administration declares in a major new policy statement that threatens to undermine decades of government campaigns for gas-thrifty cars and other conservation programs.