The thing most Americans fear is to have another nation impose its religious beliefs upon them or worse, to have one religion become so dominant that it can displace all of their religious convictions with its own set of beliefs.
Most Native Americans had no choice when it came to religion. The United States government divided the Indian reservations up like so many pieces of pie and different religious groups were given land to build churches and schools in order to indoctrinate through education. Children were oftentimes taken from their homes in the middle of the night and hauled away to these religious and state-run boarding schools. The policy of “Kill the Indian; Save the Child” was the pogrom intended to acculturate and assimilate those people the United States could not otherwise conquer.