His article draws from a Democracy Corps study based on a series of focus groups they conducted with loyal Republican voters. It says,
"Evangelicals represent the largest group, followed by Republicans who identify with the tea party movement. “Moderates,” the third group, make up about a quarter of the party’s base, according to the pollsters.
Fear of a changing society is one thing that unites all three factions. The battle over Obamacare, write the study’s authors, “goes to the heart of Republican base thinking about the essential political battle."