Romans 8:20-23 New International Version
20 For the creation was subjected to frustration, not by its own choice, but by the will of the one who subjected it, in hope 21 that the creation itself will be liberated from its bondage to decay and brought into the freedom and glory of the children of God.
22 We know that the whole creation has been groaning as in the pains of childbirth right up to the present time. 23 Not only so, but we ourselves, who have the firstfruits of the Spirit, groan inwardly as we wait eagerly for our adoption to sonship, the redemption of our bodies.
One of the reasons why the aims and hopes of 'Christian' Nationalism will always disappoint is because any success that may be achieved in this world with respect to the Kingdoms of This World will always turn out to be Fool's Gold. The true gold of a pure and righteous kingdom is impossible in this age. The entirety of Creation, Paul tells us in Romans has been "subjected to frustration," a status that it will continue to suffer under until that day when Christ returns and establishes his kingdom, the Kingdom of God.
Because of this foundational truth, power in this world will always be tainted, it will always come with warning signs and caveats. Don't get me wrong, this world needs righteous people in its leadership, we have had more than enough of evil men wielding power, but ultimately all such efforts at human self-improvement will come to naught. There is value in nonetheless striving to build and maintain more ethical governments, but such efforts need to be recognized as at most a stewardship until the final triumph of Jesus Christ.
'Christian' Nationalism unfortunately, and dangerously, sells its followers on the idea that if "we" were to wield power things would be different. The false hope is that a panacea on earth is right around the corner, if only "we" had more power. "They" are not to be trusted with it, but "we" could be. In reality, disciples of Jesus Christ ought to know better. We are sojourners in this world, our citizenship is in heaven, and our service is that of self-sacrifice on behalf of the Kingdom of God that is coming.