Negativity and presidential campaigns -- The runaway races of 1964, 1972, and 1984 -- The somewhat competitive races of 1988, 1992, and 1996 -- The comeback races of 1968 and 1976 -- The dead heat race of 1960 -- The dead heat race of 1980 -- The dead heat races of 2000 and 2004 -- Summary and synthesis : have presidential campaigns become more negative? -- Appendix: Cold War background to 1960 presidential contest.