Mark my word, if and when these preachers get control of the [Republican] party, and they’re sure trying to do so, it’s going to be a terrible damn problem. Frankly, these people frighten me. Politics and governing demand compromise. But these Christians believe they are acting in the name of God, so they can’t and won’t compromise. I know, I’ve tried to deal with them.

Barry Goldwater

Also relevant:

https://www.washingtonpost.com/archive/politics/1981/09/16/goldwater-lashes-religious-pressure/b1caa379-49fa-4e04-82de-dccda6f5e7f9/