Republicans are now a lot more religious than Democrats, but they may not mean our religious views drive our politics. Instead, people may be choosing their religious or secular affiliations, communities, and beliefs on the basis of their partisanship. Michele Margolis finds that young adults tend to move away from religion, but only Republicans and Black Democrats come back when they start a family—leading to a big over-time decline in religion among White Democrats. But what is replacing religion for Democrats? David Campbell finds that an aversion to the religious right makes Democrats adopt secular identities and principles. Both say we should expect continued religious and political polarization, as secular and Democratic identities become more closely aligned.
I dunno. I was liberal before I started sliding away from orthodox Christian belief — and a lot of my liberalism is informed by beliefs the church shaped in me. But your mileage may vary.