Contrary to such compartmentalization, the Bible tells us about Jacob (the Patriarch Israel) who dreamt at Bethel that a stair connected earth to heaven and the angels of God ascended and descended to it. The vision speaks volumes; but one fact is that God is not just a disconnected transcendent; He is connected to this world. The universe is not a closed system; God does interfere with human history; He is sovereign over it.
However, when we speak about God in the secular, we do not disconnect Him from the God of the universal Church. There is one God, God the Father of our Lord Jesus Christ. Further, the separation of Church and State is not compartmentalization of authority. God's authority is singular. His Lordship is universal. The compartmentalization is with regard to the Church - "What is Caesar's must be rendered to Caesar and what is God's must be rendered to God" when it comes to matters of religion versus politics. In other words, the Church is the House of God; the secular world is not. God's presence in the world is redemptive and reconciliatory. His Spirit is what prevents the mystery of iniquity from overtaking history (2Thess.2). Hell will break loose on earth the moment the Spirit is taken out of the path. God's presence through the Spirit is to convict the world of sin, righteousness, and judgment (John 16:8). Interestingly, it is in the political arena (of civilian concerns regarding law, justice, and peace) that these concepts gain distinct relevance. The Law is both social and personal. And, the Law is written in human hearts on tablets of flesh (Rom.2:15). However, political authority is based on a different covenant, which is prior to both Israel and the Church.
It is based on God's Covenant with Noah after the Flood. There He established violence and terror as the tools of human government to execute temporal justice on earth. In fact, "fear" had to become an important factor in the survival of humans. Thus, even the animal world was brought under the purview of fear.
"The fear and dread of you will fall upon all the beasts of the earth and all the birds of the air, upon every creature that moves along the ground, and upon all the fish of the sea; they are given into your hands." (Genesis 9:2)
Then, with regard to human government, he declares:
"Whoever sheds the blood of man, by man shall his blood be shed; for in the image of God has God made man." (Gen.9:6)
Of course, the promise of the Covenant is that God will never destroy humanity by means of a global flood, as He had done in Noah's time; and the Rainbow was given as the sign of the Covenant with the nations.
The authority of the Church, however, is not physical. It is spiritual; the tools are also spiritual.
"For though we live in the world, we do not wage war as the world does. The weapons we fight with are not the weapons of the world. On the contrary, they have divine power to demolish strongholds. We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ. And we will be ready to punish every act of disobedience, once your obedience is complete" (2 Cor.5:2-6)
"For our struggle is not against flesh and blood, but against the rulers, against the authorities, against the powers of this dark world and against the spiritual forces of evil in the heavenly realms." (Eph.6:12)
While fear is the element of crime-prevention in the political world, love is the binding element of the community of believers in Christ.
"For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and he will commend you. For he is God's servant to do you good. But if you do wrong, be afraid, for he does not bear the sword for nothing. He is God's servant, an agent of wrath to bring punishment on the wrongdoer." (Rom.13:3-4)
"By this all men will know that you are my disciples, if you love one another." (John 13:35)
Perhaps, we can say that political authority reflects the judicial face of God while ecclesiastical authority reflects divine mercy and love. Significantly, it was the religious powers of Jesus' day, deprived of political power, who used the secular political authority of the Romans (who wished not to meddle with religious matters) to crucify Jesus. The Bible tells us that in Jesus Justice and Love kissed each other. The Bible does point to a future time when the kingdom of the world will become the kingdom of our Lord and His Christ, and He will reign for ever and ever (Rev.6:15). It also talks about the saints who will reign with Him and judge the angels. But, as long as the kingdom of the world remains (secular politics), the world is still under the Noahic Covenant. It may accept or reject God, but the authority is still sacred; its violation certainly gets historically punished (through sword (war), famine (economic collapse), or pestilence (diseases)). We cannot bypass the Covenants by which God deals with humanity if we desire to understand history from a Biblical perspective.