Ostensibly, you can tell how someone votes by which church they attend.

The idea, rapidly becoming a truism, is this: Culture-warring evangelicals vote hard-line Republican, reform Jews vote Democrat, and Catholics are a tossup. Black Protestants vote Democrat, but anti-gay; Unitarians vote as progressive as possible (and volunteer with MoveOn.org).

It is not, of course, that simple. Tax codes prevent pastors, ministers, bishops and rabbis from espousing partisanship from the pulpit, and there is ideological variation in the population. No one will argue, though, that religion does not have a compelling role in American politics.

That compelling role, far from being a mere subject of research, poses a critical threat to democracy — not only because it relies on unquestioned assumptions and gospel truths but because its demands frequently oppose those of a vibrant, pluralistic society in which democracy can thrive.

Studies have shown that people who score higher on scales of religiosity are more likely to participate in traditional political channels, like voting. The amount of god in someone’s life seems to have a causative effect on her or his desire to bring the world into alignment with specific religious ideals; Pew surveys suggest that conservative voters are more likely overall to cite religious beliefs as “the most important influence on their opinion.”

Take the recent struggle over gay marriage; Bob Vander Plaats, scion of the religious right, has issued a letter encouraging pastors to sign on to his agenda to prove that the majority oppose same-sex marriage. The document is grounded firmly in religious convictions, establishing marriage as both a societal institution and one created by God.

Once one believes in an all-powerful, wholly benevolent deity, it is foolish to deny that vision of a perfect world. But lockstep religious fervor has a regrettable tendency to stray toward the authoritarian.

Faith has the power to stifle the effect of education and free exchange of ideas; the phrase “blind faith” exists for a reason. Believing that one has the sole, honest truth leads to a hegemonic assertion of dominance that is exhibited in groups from the most pathetic guru to large-scale institutions. The frequent monotheistic religious emphasis on obedience to (divine) authority is, by definition, undemocratic. Scientific studies have shown that authoritarianism plays a mediating factor in the clash between religion and pluralistic democracy, and that religiosity and authoritarianism are correlated — but not identical.

No wonder the Muslim prayers and trappings of the Egyptian revolution are viewed by conservative pundits as indicative of an Iran-style Islamism.

But it is these particular demonstrations, with their calls for democracy (rather than increased Islamic law), that have the power to inspire hope for populist religion. Muslim repudiation of dictatorship is not unique, either; from Tolstoy to the Berrigan brothers, Christianity teems with antiauthoritarian believers who focus on freedom and democratic self-governance. The Sermon on the Mount’s call to respect only teachings that bear good fruit in this world serves as a cornerstone to these views.

Contrary to anti-theist perspectives, religion does not by necessity imply authoritarianism. The same study that has found a correlate between religiosity and authoritarianism finds that the two are, still, separable. Religion that emphasizes personal experience with the divine, and a free-flowing exchange of ideas across personal and ideological boundaries, can serve an important role in the horizontal spread of information and experience.

If religiosity compels people to vote, it is best when that religion is rooted in democratic values: openness, tolerance, and positive approach toward education. Doctrine, sect, denomination, and political affiliation are irrelevant — as long as the institution rejects dictatorial rule.