Christianity is a faith that comes about as the result of individual conversion. There is no such thing as collective conversion.
If you really want to see what a "Christian nation" would look like, which would be a country in which the majority of its people had converted to Christianity and determined to live by Christian principles, look at the first century Christian church in Jerusalem as described in the first few chapters of the book of Acts. They lived communally, holding everything of material wealth in common, and distributed it as it was needed. Becoming a member of the community was based solely on conversion to Christianity, not on race or nationality or language spoken. And they governed themselves congregationally, when an issue arose or a question that would affect the whole community came up, they gathered together and made the decision as a body by consensus (Acts 4:32-37; Acts 6:1-6; Acts 15:22-35).
Christian faith dies when it is imposed. It becomes tyrannical and self-serving. The history of the church as an agent of and institution of the state is anti-Christian, adopting doctrinal standards that were contrary to the teachings of Christ and the apostles, distortions and impositions by force. The entire history of the persecution of Christians in western civilization is a persecution of true believers by an institutional, state church bent on enforcing conformity. That's exactly what white Christian nationalism does. Look at how Native Americans were treated in this country, all in the name of "conversion" but really in the name of a philosophy of Christian nationalism known as "Anglo-Israelism", the idea that God had "chosen" white people and given them a fresh start on a new continent in order to re-establish his kingdom on earth. That's not a Christianity based on any Biblical theology or doctrine.
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