- According to Wikipedia, the phrase “third rail” is defined as “a metaphor in politics to denote an idea or topic that is so “charged” and “untouchable” that any politician or public official who dares to broach the subject would invariably suffer politically.” This most certainly applies to 9/11. http://911truthnews.com/methinks-thou-dost-protest-too-much/ 27 comments reddit.com