Here endeth the debate
I used to debate lefties a lot. Now I just point and laugh. People like Brian Leiter are the reason. Here's a post from a progressive (i.e. leftist, in my dictionary, although the poster might take issue with that) that takes Leiter to task and quite effectively.
Of course, nobody who needs to read it will read it.
One of my favorite moments in many of my past discussions with leftists is always the part where they start typing, "*sigh*" before repeating one of the points that I've asked for clarification on (sans clarification, of course. Repetition by itself is not clarification.) I know that the orgasmic finish can't be far behind: wherein I am informed that I'm just stupid or crazy. I always like to respond, "Dang it, I was about to pull out the old 'you must be stupid or crazy' argument but you people always beat me to it."