Michael Jordan once said that the most peaceful moments of his life were on a basketball court, because that's the only place he knew exactly what to do. And to me the most peaceful moments in my ministry are in the pulpit because that's when I really know what I'm going to do.
Any communitys arm of force - military, police, security - needs people in it who can do necessary evil, and yet not be made evil by it. To do only the necessary and no more. To constantly question the assumptions, to stop the slide into atrocity.