There exist false teachers today who say Jesus is not going to return bodily to the earth; therefore, He wants Christians to establish His kingdom on this planet for Him. Our goal as Christians, then, would be to "Christianize the world," elect officials to high office, and permeate our society with Christian ideals. Thus, we would establish God's kingdom for Him.
This may sound nice and somewhat appealing, but it is not biblical. The Bible does not present a scenario of a world that gets better and better until Christ comes back. The Bible presents a scenario of a world that gets progressively worse. In fact, Jesus Himself said, "When the Son of Man comes, will He really find faith on the earth?" (Luke 18:8).
Our goal on earth as Christians is not to "Christianize" the world, but to preach the gospel and to keep our hold on the world as light as possible. I'm not opposed to Christians being in politics. I think we should try to do what we can to pass laws that protect our Judeo-Christian heritage. However, if we substitute these things for preaching the gospel, we're losing our focus. These things are good in their proper place, but we must first realize that we are the children of the King, and His earthly kingdom is still in the future. Our primary purpose is to seek to bring people to Christ and to live godly lives ourselves.