Which religious group has the most control over the GOP?

[Person Man]

Well, if you look at the 2012 exit polls, 26% of voters said they were Evangelical Whites and 78% of them said they voted R. That means about 42-43% of all R voters are white Evangelicals. Catholics were 25% of the R vote. So yeah, white Evangelicals are probably the biggest block R block. 

So in a way, the Republican Party is a complicated scheme where Big Business supplies the money and Fundagelicals provide the votes. Though wealthy people voted more R than they usually do.