Fascinating. www.livingroomcandidate.org allows you to view presidential campaign commercials going all the way back to Eisenhower.
I looked at some of the 1992 Clinton/Gore commercials, and one thing has become abundantly clear: we are a more liberal country than we were back then. Bill Clinton '92 would have been the most conservative candidate in the entire Democratic primary this year, and probably the most of any of the '04 crowd as well. Most of his commercials are geared toward cutting taxes, punishing criminals (prominently noting that he supports the death penalty), and "ending welfare as we know it."
16 years later, Barack Obama can openly attack his Republican opponent for not supporting "a woman's right to choose," and both candidates are trying to out-green each other, with frakin' T. Boone Pickens trying to outdo both of them!