Here’s a book called The Political Brain: The Role of Emotion in Deciding the Fate of the Nation. It looks quite fascinating because it raises some really good points on how Americans decide to vote.
In politics, when reason and emotion collide, emotion invariably wins. Elections are decided in the marketplace of emotions, a marketplace filled with values, images, analogies, moral sentiments, and moving oratory, in which logic plays only a supporting role. Westen shows, through a whistle-stop journey through the evolution of the passionate brain and a bravura tour through fifty years of American presidential and national elections, why campaigns succeed and fail. The evidence is overwhelming that three things determine how people vote, in this order: their feelings toward the parties and their principles, their feelings toward the candidates, and, if they haven’t decided by then, their feelings toward the candidates’ policy positions.