As Godwin’s Law is to Nazism, there should be a Someone’s Law for Racism.
The original: “As an online discussion grows longer, the probability of a comparison involving Nazis or Hitler approaches 1 (100%).”
The racism version: “As an online political discussion grows longer, the probability of an invective involving racism approaches 1 (100%).”
... with the similar implication that when it happens, the argument is lost.
If we're gonna do it we should do it right. As Hitler was a Nazi's Nazi, Jesse Jackson is a racist's racist.