American Christians?

Why is it that so many Christians in America are hell bent (yes that's intentional) about mixing their faith with their nation? I really wonder what it is that is motivating people to do such a thing. Is there some latent desire to return to the medevial age and the dominance of "Christian" values upon the larger society? Is there some strange belief that says to people once we become a Christian nation then everything will be right with the world? Maybe then Christ will return, as if it's something we can quicken, and the righteous USA will stand alone on the right hand of God. I think this issue really comes out regarding the 10 commandments being allowed in the classroom and most recently the debate over intelligent design being taught as science in the classroom. If the 10 commandments are allowed to be placed in the classrooms what exactly is won? If the school system is forced to teach the idea of intelligent design, what's been gained? Maybe the people who are pushing for these things really want a kind of theocracy like that of ancient Israel (nothing to do with the modern state of Israel!!!!!) How scarry would that be the think that our president would even concieve that he is carrying out the mission of God thus validating everything he does and simultaneously silencing any oppositionn. Of course those knowing the OT would realize that even the king was to be held accountable. Look at the story of Nathan rebuking David after Bathsheba-gate. Nathan wasn't killed because David knew he was to be held accountable to God. It seems today that those using God to carry out their own agenda forget that God is above them and not in their hip pocket ready to be taken out and used against adversaries.
It seems a good reading of Revelation should innoculate us agianst such thinking of mixing government with religion. The big question that Revelation presses is that there are two kingdoms, two camps, two loyalties: God's and the world's and which one will we as Christians place ourselves. Will we place ourselves loyaly at God's feet or will we sell out and give our government permission to do whatever it deems to be "God's will?"
There's also the thought that one wonders what kind of Christianity do people think of when they want the 10 commandments on the wall and want our nation to be a Christian nation. Are they thinking of wanting to spread the gospel of the kingdom of heaven, that is, the message of redemption through Jesus Christ and the continuous working of the Holy Spirit to transform and redeem all of humanity? or something else? It seems, to me, that those wanting to mix their faith with government are really concerned with a level of appearance. Or maybe the concern is legitimation. No one wants to be the minority and if Christians are the minority population in this nation then there is a loss of legitimation in the public eye. Maybe there's a fear that if less than most of a population accepts the gospel it (rather they) will be seen as inferior and irrelevant. They might be seen as stupid people who in the face of overwhelming public belief still cling to the old and worn out beliefs of an ancient and ignorant people.
It seems, though, that the Christianity of the Bible I read is one that is to be transformative and never to actually have official governing authority in this world. The point of Christianity is not to create a version of God's kingdom here, but to spread the gospel the seed of the kingdom of God so that at His choice and timing, He may be the one to bring His kingdom into this world and make all things new.
I think if we spent as much time and effort spreading the saving message of Jesus Christ and discipling people to become mature committed CHristians as we did everything else that seems not to matter most of the people in our nation may acutally be authentic Christians.