Discussions of the current political situation and comparisons between the 2008 election and earlier contests frequently overlook a crucial fact. As a result of changes in American society, today's electorate is very different from the electorate of twenty, thirty, or forty years ago. Three long-term trends have been especially significant in this regard: increasing racial diversity, declining rates of marriage, and changes in religious beliefs. As a result of these trends, today's voters are less likely to be white, less likely to be married, and less likely to consider themselves Christians than voters of just a few decades ago. The...