The same thing happened recently when a conservative walked out of the Michael Moore 911 film, early. He told some big slob handing out Kerry tracts near the theatre what he thought of the movie and the guy not only sucker punched him, but chased him while the guy was trying to dial the cops and threw him to the ground! One can only hope that someday such a bozo is going to try that crap with somebody who knows how to handle themselves during violent encounters.
I had a buddy recently retired from Special Forces who performed what he termed a rectal cranial inversion on an unruly character like this not long ago. As we used to say in the army: TRAUMA.....TEACHES!
You have to be careful about that tough. It would be my luck that I'd kick some guy in the gut and his heart would stop, and then I'd get the jury that wasn't overly sympathetic. It's best to avoid these things. Even if you win, you could lose.