It's a growing movement, led, as best as I can tell, by television pastors. I don't know if its fair to paint them all that way, there are probably people that would refer to themselves as a Christian Nationalist that don't have a hardline interpretation of the words, and would not try to implement biblical law.

The leaders of the movement routinely call for it though.

A useful litmus test is do they want to ban the practice of Islam and ban existing Muslims from entering the country, or not?