Today, this view does come across as a little radical because we've been raised in an environment where there is a "separation between church and state," which of course, properly defined, I agree with. The church has its role and the state has its. But I don't agree that this means the church has absolutely nothing to say to the state and the state has nothing to say to the church. Far from it! The church as the caretaker of the Word ought to have a lot to say to the state and the state as the enforcer of the Word ought to have much to say to the church as well!
I wonder if the reason why people are so opposed to such a view because we don't actually catch the fact that governments actively act for the sake of God not only in Israel but also when Israel is under subjugation by pagan nations.
Here's an example -
Ezra is a remarkable book filled with key little phrases here and there that demonstrate that even though God's name isn't written up and down every page, He is the actual hand that is moving behind everything. In Ezra 7, we find that God actually moves in the pagan king to declare that God's law could be enforced by the sword in his pagan nation.
And Ezra takes this in stride and follows the directions. He doesn't protest "oh, but that isn't my realm," but rather has a simple acceptance of yet another gift of the Lord.
25 “And you, Ezra, according to the wisdom of your God that is in your hand, appoint magistrates and judges who may judge all the people in the province Beyond the River, all such as know the laws of your God. And those who do not know them, you shall teach. 26 Whoever will not obey the law of your God and the law of the king, let judgment be strictly executed on him, whether for death or for banishment or for confiscation of his goods or for imprisonment.”
So I don't think we have anything to fear from Christianity in the government, or even a government that enforces Christianity. It's happened by the blessing of God in the past, there's no reason why it can't or shouldn't happen again. Will it fall short of the glory of God? Of course, as do all things, but I think it's a faithful step forward for a government to want to be a Christian one rather than one opposed to Christianity.
Anyone who does not gather with Christ, scatters. That's the option for you and for me, and for our governments.