This is one of those "what if" counterfactuals that serves as a proxy for people who have their panties in a knot over Christians. "What if this really bad thing came to pass? We must take stern measures now to prevent it from happening!"
Generally in risk assessment, there are two factors to consider: likelihood, and impact.
The likelihood of a dominionist takeover is a close approximation of nil. I consider it a much less likely threat than that posed by progressives, how who have a track record of becoming successively more unhinged, intolerant, and tyrannical as the masses show less and less inclination to go along with the technocratic cause du jour.
I continue to maintain that if fascism (in the proper meaning of the word) ever does come to pass in the US or Canada, it will be at the hands of the Democratic or NDP parties, respectively.
[Oops.]