I would guess that the artist is referring to the traditional slap that a doctor administers to a newborn baby to get it to breathe.(I can read the doctor's brief, but not the lawyer's...LIE-what?? Not that it matters, if my guess was correct.) Poorly done joke. Besides, the legislator withdrew the proposed spanking law. Old news.
I happen to agree with the artist that the proposed spanking law was silly; my criticism was that his message wasn't made clear--I wasn't trying to sweep an embarrassing issue under the rug. (Just in case *I* hadn't made it clear!)