However, irony works differently, even for progressive purposes, when knowledge in question concerns _real social contradictions_, not simple logical contradictions within statements or incongruities between statements and implied knowledges of enunciators. I think this is what Carrol means when he says that "irony achieves its full richness if it overlaps allegory (conceived as a story that is both literally true *and* carries an independent meaning which can be played off against its direct story)." Irony must overlap allegory when irony is used for progressive critical purposes, in that it must then take on an ensemble of social relations that really exists and actually works and yet is "false" (e.g. justice based upon "Freedom, Equality, Property, and Bentham" and a woman having to make sure that "a single man in possession of a good fortune must be in want of a wife" so she can live on his income) if seen from the point of view of the "future" that will have abolished the said ensemble productive of the very contradictions that irony seizes. Examples from Marx and Austen Carrol cites belong in this category of critical irony--irony that does not submit itself to the eternal present.
When we make this distinction between irony that merely touches the empirical and irony that cuts through the empirical and seeks to sabotage the real mechanisms that produce the empirical and the observable (irony of Marx and Austen, for instance), we may also be able to make a distinction between the kind of irony that is "a deadly sin in political discourse" (e.g. an obnoxiously cliquish inside joke and a Letterman-like jibe against "suburban dorks") and the other kind of irony that gives life to political discourse.
Yoshie