Agriculture is notoriously unstable, wrote Purdue Uni­versity economist Don Paarlberg in his classic book "American Farm Policy," published in 1964. He went on to say, "Variations in costs and returns from year to year on a given farm come largely from the vagaries of weather and market be­­havior, both of which are to a great extent beyond the control of the individual operator."

Yet when given the choice of more stability, many farmers and ranchers recoiled at the notion. Stability became an unpopular concept because it usually meant stability at low price levels and a heavy reliance on...