We teachers of argument have nothing to apologize for.
Argument has no determinable function in the sense Walton needs, and even if it did, that function would not ground norms for argumentative practice.
What Smith taught, what Smith said he was teaching, and what my students want to learn: they all line up.
Papers by Asen and Rehg get us halfway to an understanding of the activity of arguing in the public sphere.
At first glance, arguing does look angry and futile. But on second view, it's more complicated.