In this paper it is shown is that although poisoning the well has generally been treated as a species of ad hominem fallacy, when you try to analyze the fallacy using ad hominem schemes, even by supplementing with related schemes like argument from position to know, the analysis ultimately fails. The main argument of the paper is taken up with proving this negative claim by applying these schemes to examples of arguments associated with the fallacy of poisoning the well. Although (...) there is a positive finding in this quest, in that poisoning the well is shown to be based on and associated with these forms of argument in interesting ways, the paper in the end is led to the conclusion that the fallacy is irreducibly dialectical. Poisoning the well is thus analyzed as a tactic to silence an opponent violating her right to put forward arguments on an issue both parties have agreed to discuss at the confrontation stage of a critical discussion. It is concluded that it is a special form of strategic attack used by one party in the argumentation stage of a critical discussion to improperly shut down the capability of the other party for putting forward arguments of the kind needed to properly move the discussion forward. (shrink)