Monday’s post generated an unusually large number of comments that consisted of nothing but namecalling, directed in almost all cases at Paul Krugman (though in exactly one case at me). I’ve deleted all of these comments, in most cases before they were ever posted.
I strongly encourage spirited discussion. I understand that spirited discussion can get pretty heated, and that in heated discussion people (including me) sometimes say nasty things. I prefer to keep that to a minimum, but I still allow a fair amount of it as long as the comments advance the discussion. But if your post consists of 100% pure nastiness, with no conceivable way for anybody to learn anything from it, I will usually delete it. One exception: Being very funny can compensate for a lot of nastiness, especially if it’s the kind of funny that draws the reader’s attention to a genuine flaw in someone’s reasoning. The many posts I’ve deleted over the past 48 hours were nasty without even trying to be funny.