There is no public test for religious belief for public office. Why would we want to go back to the situation we left europe in the first place for?
I also don't understand what you are saying about Europe. I thought people left Europe because they were persecuted for their beliefs. I don't think that someone not agreeing with my beliefs is persecution.
For example, some people believe that a candidate who believes the world was created in six days is not scientifically grounded enough to be President. Do you think such a candidate would be being persecuted for his religion?
No one is entitled to be President.