Godwin's Law
The phrase Godwin's Law (or Godwin's rule of Hitler analogies), coined by Mike Godwin in 1990, originally referred to a semi-serious assertion that "As an online discussion grows longer, the probability of a comparison involving Hitler approaches 1"—that is, if an online discussion (regardless of topic or scope) goes on long enough, sooner or later someone will negatively compare someone or something to Hitler.
Godwin's Law is now applied also to situations other than online situations and also to negative comparisons more generally with "Nazism".
In many cases, it is attempted guilt by association or ad hominem.
The ubiquitousness of the described phenomenon can be seen as in some cases related to Holocaustianity, with Hitler for many having replaced the Devil as the ultimate evil.
