I honestly wonder if people like this have read the Bible even a single time.
If someone wishes to be a religious leader, serve the God of Abraham, AND be politically active, there is a religion for that - Islam. Muhammad was the messenger of Allah and he was also politically active, therefore following his example would necessarily involve both.
In contrast, it is very clear from reading the New Testament that Jesus Christ was decidedly apolitical. There are no ifs, ands, or buts about it. If you asked Jesus Christ if he was voting for Pelosi or Boehner, he would say "no comment". A Christian pastor who is politically active is about as representative of Jesus Christ as Pope Urban II was when he ordered the Crusades.
Make no mistake, I am not evaluating the merits of a religious leader being a political leader. I am just pointing out what should be obvious facts: Jesus Christ was not a political leader, Muhammad was one. If a Christian religious leader believes that they should act in a political way, they should consider converting to Islam, since that religion is probably closer to their core philosophical beliefs than Christianity.