"All governments suffer a recurring problem: Power attracts pathological personalities. It is not that power corrupts but that it is magnetic to the corruptible." - Frank Herbert, Chapterhouse: Dune, pg. 59.
(http://phrases.org.uk/meanings/absolute-power-corrupts-absolutely.html) "Power tends to corrupt, and absolute power corrupts absolutely. Great men are almost always bad men." Great examples of this are Golding's Lord of the Flies and world history. I also love "Operation Stingray" posted in /r/nosleep (http://www.reddit.com/r/nosleep/comments/1sxtd1/operation_stingray_is_in_effect_god_help_us/).