Mark Lilla has written a fascinating essay entitled Coping with Political Theology, which is also the introduction to his book The Stillborn God: Religion, Politics, and the Modern West. Here’s the key thesis. Writing about the religious wars which tore Europe apart in the 16th and 17th century, he observes:
As we know, this crisis of Western Christendom prepared the way for modern political thought, and eventually for modern liberal democracy. And it seems to follow from this fact that modern liberal democracy, with its distinctive ideas and institutions, is a post-Christian phenomenon. I want to insist on this formulation as a way of stressing the uniqueness of Christian revelation and its theological-political difficulties – and therefore the uniqueness of the philosophical response to the civilizational crisis those problems triggered. Though the principles of modern liberal democracy are not conceptually dependent on the truth of Christianity, they are genetically dependent on the problems Christianity posed and failed to solve. Being mindful of this should help us to understand the strengths of our tradition of political thought, and perhaps also its limitations.
(My emphasis.)
Lilla argues that, deep down, Americans recognize this truth, which is why democracy and tolerance have trumped religiosity at every turn, and will (hopefully) continue to do so. Not all agree with him: see, for example, this troubled response by Damon Linker, and this from Philip Jenkins. In any case, it looks like a must-read book. ((Hat-tip to Sully, who also has an essay at Cato on the subject.))