Complex sentence: In 1964, Hargis, who was a staunch supporter of Republican Senator Barry Goldwater in that year's presidential race, used his radio program to attack journalist Fred J. Cook, who had written a book that was sharply critical of Goldwater.
Split into simpler sentences: In 1964, Hargis supported Republican Senator Barry Goldwater in that year's presidential race. On his radio program, he attacked Fred J. Cook, who had written a book critical of Goldwater.