Turning discourse into slogans

I
recently heard a panel discussion in which the conversation turned to the sorry
state of American political discourse, which too often descends into
sloganeering--assertions about "smaller government," "equal rights," "personal
responsibility" or "liberty," as if that ends the discussion.

One
of the panelists was biblical scholar N.T. Wright, who commented: "Turning
discourse into slogans is a classic postmodern thing to do."

His
point, I take it, is that if each person has access only to his or her own
personal truth and there is no publicly accessible version of truth in which we
all participate--as apologists for postmodernism would contend--then
disagreement can never turn into argument; it can only lead to an exchange of
personal assertions, expressed in convenient slogans.