If Paul Bloom (and the sociologists he quotes) is right on this, the battle lines in American politics are very strangely drawn:
the religious divide between Americans and Europeans may be smaller than we think. The sociologists Rodney Stark, of Baylor University, and Roger Finke, of Pennsylvania State University, write that the big difference has to do with church attendance, which really is much lower in Europe. (Building on the work of the Chicago-based sociologist and priest Andrew Greeley, they argue that this is because the United States has a rigorously free religious market, in which churches actively vie for parishioners and constantly improve their product, whereas European churches are often under state control and, like many government monopolies, have become inefficient.)
So if Bill O'Reilly, James Dobson, and friends get their way and bust through the wall (which is really more of a hedge these days) separating church and state, the result will be an ossified, dumb religious movement that robs the Christian Right of its political power? Man, I sure see why Republicans are supporting and Democrats are opposing that.
To be fair, I'm simplifying the situation a bit. Arrangements would have to be made to ensure that evangelicals got the official state nod, which might be tricky considering the impending Catholic dominance of the Supreme Court. On the bright side, the added work would have the side benefit of breaking up the various odd marriages of ideological convenience currently papering over historical intrareligion tensions and creating a (mostly) unified Christian Right.