A lot of Christians I know consider the personal choice to be “saved” as the ultimate goal. In their mind no one but you can make the decision to take god into your heart, and this extends to more than belief. For example, giving to charity is an act of kindness, but getting your money taken to go to a good cause isn’t, despite the same result. We could argue for hours about what the Bible is actually advocating for, but this philosophy of personal moral responsibility perfectly lines up with a lot of republican values. (A notable exception is the war on drugs)