The Victory Lab, Chapter 1 "Blinded by Political Science"

The responses guided Campbell toward nothing less than an all-encompassing theory of how elections are decided. Along with colleagues, Philip Converse, Warren Miller, and Donald Stokes, Campbell concluded that a person's partisan identification was the strongest predictor of how they would vote in national elections, even better than asking them where they stood on any particular issue. Parties were glorified social clubs, pulling people in because of class, regional, or religious ties and keeping them for the long term -- with a sort of thoughtless choice resembling the inertia that led people to take the same jobs as their relatives. Individuals rarely switched parties over the course of a lifetime. Campbell and his colleagues described individual voting decisions with the image of a funnel: citizens' social and psychological loyalties narrow them into a party, which  usually guides them toward a candidate.

Instead, thought Popkin, it made more sense to think of [voters] as investors, who knew whatever information they gathered to inform their decision making would require time and effort. So when it came time to choose a candidate, they relied on short cuts. They interpreted symbols and looked for cues where they could find them, and then extrapolated. In one of Popkin's favorite examples, when voters saw Gerald Ford fail to shuck a tamale before biting into it, they interpreted it as a sign that he did not understand issues facing Latinos. Popkin called this "gut reasoning."

Relying on their polls for Nixon, Teeter and Steeper delivered a new theory for what had prompted so many Democrats to unmoor from their party and dock with Nixon. They suggested that swing voters were no longer voting on issues, such as Vietnam or the economy. They may not have even had strong ideas of the right and wrong positions on the issues. Now they were giving their votes to the candidate who seemed best able to 'handle' those challenges. Nixon, like Eisenhower, had established himself as a more credible leader on the issue of the day. This 'candidate-induced issue voting,' as Teeter and Steeper called it, had as much to do with the candidate as the issues.