Thomas Jefferson was a church goer, and is well remembered for wanting a "high wall" between church and government. The separation of church and state idea in western culture is often traced back to a bishop, Thomas Beckett, who had a conflict with Henry II and this led to what is credited in history books as being the beginning of separation between church and state. The end result was government officials slaying Beckett over the altar of the church he presided. Beckett was remembered a martyr, and pilgrimages to his church in Canterbury are still practiced by Christians to this day. Separation of church and state was originally promoted by Christians who recognized that spirituality doesn't flourish when handled by the government.
Regardless of how long this ideal has been part of American history, there is no denying the fear mongering, the feeding of egos, or the sense by a few who believe that the US should be a new Israel or some other idea that is basically the same has been a part of our history and is definitely part of the current election rhetoric.
I identify my spiritual path as Christian. I find it sad that when some individuals have to insist that everyone share their viewpoint and conform to their very small worldview, the whole group often gets blamed. Sadly, humans do this with religion and other causes. Extreme Nationalism is just as cultish as intolerant religious groups. The problem is bigger than religion, it is that we as humans need to confront our own fears of what is different and find ways to accept others. Religion is just one example of how this behavior shows up in politics.
Whatever people care deeply about, whatever they are insecure about, can be exploited by someone to gain power. Rather, we the people should be stopping to think about our own fears and why anyone would want to control another's free will, and then look for government officials who represent all of us for a safer, equitable and just society.
I am glad the OP opened this topic for discussion, because it REALLY needs discussed this election. Much of the talk from candidates does seem focused on gaining votes from those who are afraid rather than those who want to look at the real issues that our society is facing.