How does the Church deal with radical evil?

What is the role the church should play in dealing with people like Hitler? Is it the role of Christians to come alongside the State (wherever in the world that government is) and pick up the sword to kill and make war against those who commit radical evil. I would pose that this is not the role that Christians are to play. When God dealt with the most radical evil this world has ever known, Satan, the Devil, it was not by killing him, or destroying him flat out, it was by allowing radical evil to kill His Son. God dealt with evil by allowing it to do it's worst to His Chosen One, and then by raising Jesus from the dead. He dealt with the worst evil could do by defeating death when He resurrected His Son.
If Jesus is our example, in life and in death, how far are we willing to go with it? Jesus told His disciples to love their enemies and pray for those who persecute them. Did he then make a caveat and say that you don't have to pray for them or love them when the State says that they need you to kill "the enemy?" Where is our allegiance? If Christ didn't want us to kill for the Kingdom of God, but instead to be willing to lay down our lives for the Kingdom, then I fail to see why He would be an advocate for His followers to kill for a government that rejects Him and His ways, and that is fallen, corrupt and will not last.