One foundation of Christian Nationalism is found in Romans 1:21-22: "Because that, when they knew God, they glorified him not as God, neither were thankful; but became ->>vain in their imaginations,<-- and their foolish heart was darkened. Professing themselves to be wise, they became fools."
There are a lot of Christians who are pushing Christian Nationalism but do not know they are. Not knowing they are does not make them any less innocent. Paul points out to Timothy: "For the time is coming when people will not endure sound teaching, but having itching ears they will accumulate for themselves teachers to suit their own passions, and will turn away from listening to the truth and wander off into myths" (II Tim 2:3-4). Vain imaginations and desires for power are Christian Nationalist compatible.
Imagination is a very powerful force. Offhand I would count it as one of the most powerful forces in the universe outside of God & His Spirit. In fact, very early in our Creation story we find the Genesis author stating that in "GOD saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually." (Gen 6:5). That is man. Jeremiah added “The heart is deceitful above all things, And desperately wicked; Who can know it?" (17:9). I cant even imagine what the world would have been by now had God not sent us His Son for our redemption.
A major part of spiritual warfare is "casting down imaginations" and that applies to what I hear and what I think. I must deal with my own imaginations..while addressing the info I take in. This takes the power of the word to aid in fortifying ourselves from it and even addressing in others. Build your spiritual foundation on a rock and not sand. The next wave..which might be CN..will come your way and wipe out everything you had spiritually. And there is no guarantee you will want it back when you finally discover how far away from reality the wave took you.
For me, right now, one of the major themes I address in my reading and writing is Christian Nationalism. As I stated earlier there are many people pushing Christian Nationalism but dont know they are doing it. I can attest, but not proudly, that I spent many years pushing Christian Nationalist ideas. My ideology followed many American church teachings that suggest America has some sort of special place in creation and, from reading authors like David Barton, were convinced that God played a major part in establishing America. Granted God was there and knows what was going on but He really did not have the hand on Americas foundation that most CNs think. (and I am not saying God abdicated anything...He allowed man to do what he was doing. And in contemporary society there is absolutely no calling from God to anyone to throw out the Constitution and establish America as a theocracy. Particularly since I understand the idea is to establish the Ten Commandments as the foundation. America has a rich Christian foundation and many blessings with Jesus as king and not some theocratic political leader.
Christian Nationalism as a movement is a power play. They have a sense that they have no power and then when some apostate comes along and playa the Jesus card, they are all in. God, of course, nor Jesus ever issued those kinds of commands. There are self proclaimed prophets as we speak pushing what they claim are prophetic words from God...but they are not. They get themselves attention...and they can find ways through the internet to monetize themselves...and as long as the money keeps coming they will keep preaching whatever the donators want.
Adolf Hitler pushed Christian Nationalism in the 1930s as he rose to power. He understood the need for power many Christians have...particularly when enticed via the avenue of their own vain imaginations.