Well, there's a difference between the shepherd and his flock..
In general, church goers are a powerful group. They get pissed about stuff and get out and vote. So catering to them gets you reelected. There are christian universities which crank out future lawmakers like mad which go right into offices in washington as interns.
Thats where the liberal base struggles, inner cities, college students, etc, who vote liberal, they aren't a cohesive group. Oh, they'll get together to protest something, but thats about it.