In regards to religion itself, there can be a fine weakness in seeking government support in toto for your faith: your are at the whim and mercy of the government itself. The emperors of Rome throughout the fourth century meddled in the affairs of the church, both for good and bad. This might lead to an interesting the Arians sought their power from governmental support, and so when the empire eventually came to side completely with the Nicene faith, the Arians completely lost power. By contrast, the Nicene faith based itself on the grounds of scripture disregarding the opinion of the government, and so it could survive the tides of emperors who were oppositional, neutral, or supportive. God's word is eternal; political powers are not. Yet even ignoring the actions of individual Christians in regards to government involvement, I think a deeper question here is one that is not often addressed: God's involvement within the actions of a government system.
First, it should be established that God has, in the past, plainly stated that He was the one truly in control of the affairs of state. When the Assyrian king was looking at his massive, expansive empire and saying, "By the power of my hand and by my wisdom I did this" (Isa 10:13), God replied:
Is the axe to boast itself over the one who chops with it? Is the saw to exalt itself over the one who wields it? That would be like a club wielding those who lift it, or like a rod lifting him who is not wood. [Isa 10:15]When Sennacherib besieged Jerusalem and was boasting to the Jews of what he had done with his empire, and all the successes he had won against nations bigger than Judah, God replied through the prophet Isaiah:
"'Have you not heard? Long ago I did it; from ancient times I planned it. Now I have brought it to pass, that you should turn fortified cities into ruinous heaps.'" [2 Kings 19:25]God's point in both these passages is clear: though the leaders boasted that it was they who had done these great things, it was actually God who was in control the entire time. On the one hand, the king was simply the axe which God wielded to exercise His judgment; on the other hand, the king only had so much success during his reign because God had long ago planned that it should occur. In neither scenario was God merely reacting to what the kings had done, nor was God utilizing earthly means outside of His control to His own personal ends.
An even greater example is found in Paul's epistle to the Romans, where he speaks of Pharaoh being raised up by God:
For the scripture says to Pharaoh, "For this very purpose I raised you up, to demonstrate my power in you, and that my name might be proclaimed throughout the whole earth." [Rom 9:17; ref. Exo 9:16]Let me expel a common straw man right off the bat: this does not mean that God controls political leaders like puppets or robots that He controls with a remote control. Pharaoh, the kings, etc., had as much control as they believed they had. However, God's will and purpose was sovereign over their individual wills and purposes. The kings of Assyria, for certain, all believed that they were really the ones in charge of their own destinies and empires, but in actuality God had complete, sovereign control over their fate. Their growth in power was merely part of God's purpose for His will.
This leads us to discuss how God interacts with governments in our modern day and age. Over the past few days, I've heard some rather peculiar things in regards to this, and, living in a democracy, they are very relevant: 1) God only involves himself within a democracy if people pray for the results; 2) God did not bring any president to power because the previously mentioned passages in the Bible are referring to hereditary kings and not elected officials.
Responding to the latter first, this is a blatant example of begging the question. Nowhere does God say that He only has power over a government if there is a hereditary monarchy in place. The only reason hereditary monarchies are focused on in the Old Testament and partially in the New is because no real democracies were interacting with the land and people at that time. Likewise, it was never emphasized that the kings were used solely because they belonged to a hereditary form of government - God emphasized that it was their power He was raising and utilizing, not their monarchical structure.
Might I propose that this, logically speaking, also means man found a way to usurp God's will and purpose? Since representative democracies, republics, etc., are all man-made forms of government, reason follows that we are now arguing that man found a form of government which God's will and purpose cannot touch. Man, in essence, found a loophole in the system, in which governments can act contrary to God's final purpose.
Moving to the first part second, nowhere is it shown that God is limited by the collective decisions of individuals. To understand this, let's review one of the biggest "elections" in the New Testament:
Pilate said to them, "Then what shall I do with Jesus who is called Christ?" They all said, "Crucify Him!" [Matt 27:22]Pilate held one of the biggest referendums in history: should Jesus be crucified? The resounding answer from the population: yes. Was this something God could not control? On the contrary - God had already predestined this to occur.
For truly in this city there were gathered together against Your holy servant Jesus, whom You anointed, both Herod and Pontius Pilate, along with the Gentiles and the peoples of Israel, to do whatever Your hand and Your purpose predestined to occur. [Acts 4:27-28]Even in the willful decision of the Jewish population, Christ was in control. The election, in fact, was part of God's purpose. The Jews did not pray before "electing" to crucify Christ, yet their decision still fulfilled His purpose (the crucifixion, resurrection, etc.). To the disciples and many others, things were not going the way they had hoped. Everything seemed lost. Yet, to put it colloquially, it was, for God, "all part of the plan." Even in the lowest moment of man's treatment of God, God was nowhere near thwarted, and the will of those who crucified Christ was still subservient to the ultimate will of God. Even in the case of elections, referendums, or general public decisions, God is as much in control as He is in the general decisions of hereditary monarchies.
The point of all this is to present that, regardless of governmental decisions, God is still in control. Whether the president whom we want to be elected is elected or not, God is not thwarted. This also means, whether we like the president or not, he is there by God's will and purpose. We will not know how he fits there until perhaps decades after his terms are over, but nonetheless this is a theological truth we cannot deny.
In all things - whether we discover the truth sooner or later - soli Deo gloria.