By Richard Winger On July 6, former U.S. Senator Alan Dixon (D-Illinois) died at 86. See this obituary. Senator Dixon was the most persistent advocate of federal legislation setting up regional presidential primaries. He introduced such bills in 1987 (S.1786), 1989 (S.377), and 1991 (S.288). The bills would have divided up the United States into presidential primary regions.(More)…