In an uncharacteristically combative and mocking blog post, Greg Mankiw attempts a smackdown of our very own Professor J. Bradford DeLong. I respect Professor DeLong as an economist and Professor, but I am less fond of DeLong the partisan blogger. Although he often skillfully dismantles wrongheaded right-wing arguments, he also occasionally shoots from the hip and treats his intellectual opponents uncivilly.
This time, Mankiw is fighting back, and is using some of DeLong’s trademark insults in the title of his post. Basically, DeLong used a faulty assumption about what will happen to certain taxes in the future to conclude that the Simpson-Bowles tax plan is regressive, that is, that the budget will be balanced on the backs of the poor and middle class to the benefit of high-income earners. Correcting for this bad assumption, Mankiw points out that the plan is, in fact, progressive.
I haven’t looked into the specifics of the argument, but DeLong will almost certainly respond on his blog if there are any remaining holes in Mankiw’s rebuttal. If that happens, I would warn Mankiw against getting in too deep against Professor DeLong. If things get ugly, it will be Mankiw whose clean reputation in the blog-o-sphere stands the biggest chance of becoming sullied.