It's often like the force of gravity in American politics and it has been gaining power for about a quarter of a century. We're talking about the "pew gap," that mysterious X-factor that keeps showing up in surveys about the most controversial political and social issues in this land of ours. Simply stated, the more often a person sits in a pew inside a religious sanctuary, the more likely they are to vote for morally conservative candidates (in either party, but these days this tends to show up as a GOP bias).
So does his mean (a) that all moral conservatives are Republicans? The answer, of course, is "no," especially when you start hanging out with Latinos, African-Americans and people in blue-collar jobs and/or labor unions.
Does this mean that (b) all Republicans are moral conservatives? The answer, of course, is "no," especially when you are dealing with country-club members and people far outside the Bible Belt.
Does this mean that (c) cultural liberals are godless heathens who never go to church? Of course not, but they are a minority of those found in pews and they tend to be active in smaller, doctrinally progressive flocks of all religious brands.