Voting: Christian duty or not at all?

With the 2008 election ramping up, I've been thinking about voting. There are some circles of Christians who feel that voting in any election is confirming your citizenship in that country instead of in the kingdom of God. It's something to think about. For a while now, I've tried to think of myself as a citizen of the world, with all people as my comrades. When we studied the beginnings of communism in my Western civ class, Marx and the others thought it was a bad idea to think of communism as a nationalist movement, but that instead communists should think of all other communists as citizens of the same government. (I rue this day in which I have summoned the name of Marx in a blog post!) This closet socialist likes that idea. (Is the FBI going to come knocking soon?)

When I vote in an American election, am I isolating Christian brothers and sisters in other countries? Do I make a bad Christian anarchist because I submit to this government? Am I not putting my faith in God and his people to be independent hands of Christ? On the other hand, if I don't vote, am I doing a disservice to the people that could be helped in America by government programs on account of my vote? Going further, is it my Christian duty to encourage people to vote a certain way because it will serve poor people or foster children or elders, which I believe Christ would have done?

Jesus didn't live in a society where most of the people he talked with would have had the option of voting. He just said to give to Caesar what is Caesar's and God what is God's. Is this democracy thing something that Christians are supposed to get involved in? I've tried to stay informed on political events. In 2004, I started to be a talk radio junkie, and I still am. But should I be? In 2004, a friend called out her fellow Christians and said that if we put the effort that we spent on politics into serving Christ, how much the world could change. That's been bugging me.