Godwin's law

Godwin's law, formulated by the American attorney and author Mike Godwin, asserts that "as an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1". Godwin originally referred to Usenet newsgroup discussions, but the rule is now also applied to other forms of online threaded discussion mediums, like forums and chat rooms.

There's a tradition in some online discussion groups that, as soon as a Hitler comparison is made, the person making that analogy loses the discussion and the debate is over. On the other hand, there's the danger of the principle being used as a distraction, when referring to an actually valid comparison as hyperbole.

In December 2015, in the context of Republican presidential candidate Donald Trump, Godwin stated: "If you're thoughtful about it and show some real awareness of history, go ahead and refer to Hitler when you talk about Trump, or any other politician."