Poisoning The Well

I haven't heard the phrase come up since my childhood debate class, and before that a humorous short story called "Love is a Fallacy." Perhaps naming it will help draw some of its strength. Poisoning the Well is a rhetorical device, something like a fallacy though not quite, in which a person impugns the character or motives of an opponent before s/he has the chance to speak. It is in operation these days whenever someone accuses another of racism for weak or spurious reasons, forcing them to look bad by even having to defend it.