Allen J. Ellender was a loyal lieutenant of Huey Long's Louisiana political machine during a sixty year political career that included 35 years in the United States Senate. He was the Majority Leader of the Louisiana State House of Representatives while Long was Governor, and went to the Senate in 1936 after the Kingfish was assasinated. The old-fashioned Southern Democrat served as Chairman of the Senate Approriations Committee and as Senate President Pro-Tempore — third in the line of presidential succession.
In 1972, Ellender, 81-years-old and considered to be in good health, was a candidate for re-election to a seventh six-year term. He drew two primary opponents– 39-year-old moderate J. Bennett Johnston, who had served one term in the Louisiana State Senate before waging an unsuccessful bid for Governor in 1971 — and political unknown Frank Allen. Few pundits believed Ellender was at any real risk of losing.
But on July 28 — just 22 days before the Democratic primary — Ellender complained of stomach pains during a flight back to Washington. He died of a heart attack shortly after.
The Deborah Poritz of his era, state Attorney General William Guste, issued an opinion that Ellender's death required a postponment of the primary so that oher candidates could enter the race; Guste was a possible candidate. But instead, the Louisiana Democratic State Committee — afraid that controversial former Governor John McKeithen could emerge as their candidate — voted to proceed with the primary — handing Johnston the nomination, virtually without opposition. Meanwhile, Governor Edwin Edwards — now serving a ten-year prison sentence for racketeering — appointed his wife to fill the vacant Senate seat.
According to published reports, the U.S. Attorney was prepared to indict McKeithen on charges that he took kickbacks from insurance companies in exchange for state contracts — but dropped their investigation at the request of U.S. Senator Russell Long, the Kingfish's son.
McKeithen entered the race as an Independent, but Johnston won 55%-23%, with 19% for the Republican candidate, Ben Toledano. Johnston remained in the U.S. Senate for 24 years, before retiring in 1996.