One of the most skillful orators and most successful politicians of the 1920s and 1930s, Hugh Pierce Long was a demagogue, but one with strong populist appeal. Long was elected governor of Louisiana and then U.S. senator, and, had his life not been cut short by an assassin's bullet, he might have posed a formidable threat to Franklin D. Roosevelt's tenure in the White House. He is immortalized, in a thinly disguised version, in one of America's great political novels: Robert Penn Warren's All the King's Men.

Born into a middle-class Louisiana family, Long studied law for a year before gaining admission to the Louisiana bar in 1915. A few years later, he was elected to the state's Public Service Commission, which regulated the oil companies that were such an important part of Louisiana's economy. Long became known as a critic of the oil...