Let me add one more definition to the picture to heighten this tension. In economics and political science, it is common to define the government as the entity that holds a monopoly on violence. This definition goes back to Max Weber, but it is used by recent Nobel laureates in economics as well. It does not mean that the State alone uses violence, but it does mean that when push comes to shove, the State will win in a battle of wills. If you refuse to pay your taxes, you will lose. You will go to jail, and if you fight, you will lose. The government holds a monopoly on violence. Any law that we vote for is ultimately backed by the full force of our government and military. Do we trust institutions of the government to ensure justice? Is that what history teaches us about the State? Or do we live in particularly lucky and fortunate times where the State can be trusted to do minimal justice? The State's budget is currently about $3 trillion a year. Do you trust that power to the political Right? Do you trust it to the Left? If you answered "no" to either question, you may have a major problem in the future. See Plato on the regime that follows democracy.
So now, I hope you are feeling even a bit more ill-at-ease. The logic above is inescapable for a Christian. If we Christians vote for what we consider to be good policies, we are ultimately voting to ensure that our will is carried out by the most powerful force on earth, aside from God. The U.S. government has a monopoly on violence, and that force underlies the law of the land.
Do we have the right to coerce our fellow citizens to act in ways that follow our Christian ethical beliefs?
Darn Tea Party crackpot partisan ignoramus.