THREE WORDS: AMNESTY, ABORTION, ACID.
Read Hunter S. Thompson's Fear and Loathing, on the Campaign Trail '72.
Also, there were no debates that election. There was the 60 debate between JFK and Nixon, then no Presidential debate until 76 between Ford and Carter. In many elections the debates have been a huge factor.
60, Nixon looked haggard and ill. That along with some voter fraud gave Kennedy the election.
76, Gerald Ford said Poland wasnt under Soviet domination. That may have cost him the election as Carter won a close race.
80, Reagan says "Are you better off than you were four years ago" and turns dead heat race into a landslide.
88, Mike Dukakis responds cooly and dispassionately to a question from Bernard Shaw about whether he would favor the death penalty if his wife Kitty was murdered. A close election turns into a rout.
92, George HW Bush looks at his watch and appears out of touch.