"As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches one."It is often misunderstood as a claim that the person making the comparison has lost the argument, or that the discussion has ended. There is additionally a Godwin's law of time travel to the effect that once time travel enters a sci-fi series, the probability of the hero using it to try and stop the Holocaust approaches one.
I have chose the word parallel, as my similar observation is not a corollary, axiom, postulate, or lemma. But it's got to be a something, so I chose Parallel.
As an online discussion grows longer, the probability of a comparison involving McCarthyism also approaches one, but more slowly than Godwin's Law.