Here is a dirty little secret: Every government on earth is a theocracy. Every government in human history has been a theocracy. All authority flows from Almighty God, as we learn in Romans 13. Therefore, we are to obey the civil magistrate that draws authority from God, unless that government orders us to disobey the higher law we find in Scripture. Christians should be the best citizens a righteous government can have.
Remember, when Pilate told Jesus Christ that he had authority to crucify Him, Jesus reminded Pilate that he would have no authority had it not been given to him. Therefore, because governments derive authority from God, governments should obey and submit to Him in all they do. God will hold them accountable for rebellion and abusing the authority He gave them, just as they will hold us accountable for how we deal with wicked or righteous behavior by our civil magistrate.
Governments can, of course, deny that their authority comes from God. They are wrong, and they should be consistently reminded that they are wrong. The Constitution of these United States is a brilliant document that understands the depravity of man and why government’s power must be limited, but even the Constitution is ultimately subservient to God’s Law. We can deny that all we want now, but when we stand before the King of Kings we will all bow the knee and confess that Jesus Christ is Lord of all. That is why we as Christians should not be ashamed to confess this truth in public.