"Religious currents are more pervasive and more multifaceted than ever in shaping the public debate," says Allen Hertzke, a professor of political science at the University of Oklahoma in Norman. While religion historically has influenced politics, affiliation was typically the dividing line: Protestants voted Republican and Catholics voted Democratic. "Patterns now suggest something unusual in American politics – division along the lines of salience of religion" itself, says Professor Hertzke. "This year, it has intensified."
The enduring points of division seem to be legal abortion and gay marriage – issues unimaginable a generation ago, when compromise characterized politics. "If someone is a Republican or Democrat because of the abortion issue, they tend to interpret a whole range of issues through that lens," says John Green, a professor at the University of Akron in Ohio.
This year, the arena of reproductive issues and health care in general has spilled out into a battle over religious liberties. And though it roughly follows party lines, for some the issue crosses partisan boundaries.
More than anything else, the degree of "religiosity" now seems to divide voters, says Professor Green. People who are very religiously observant – those who go to worship services, read theScriptures, pray – tend to be Republicans. Secular people, along with black Protestants, nonpracticing Jews, and some practicing Catholics, tend to be Democrats. As Hertzke puts it, "Even if you ask about something as simple as grace before meals, you can tell if a person is likely to vote Republican."
Of course, some voters defy categorization, and the campaigns will battle fiercely for them.