Try Nixonland by Rick Perlstein. It's more of a Nixon biography, but it does describe the 1968 presidential election in great detail, especially the George Wallace campaign and the Democratic National Convention.
I read part of that book. I liked how it focused on individuals, with a chapter devoted to Reagan (though it's possibly tainted with bias), and with other people. I like one of the pictures in the middle where it has Romney, Reagan, and Rocky and the caption reads "some anti-war figures wore suits" referring to Romney.
