I try to resist an overwhelming temptation to view Krugman as clever but evil, and DeLong as decent, but somewhat dim. Who knows...perhaps we are all these things some of the time?
DeLong certainly appears to have a lot of "energy." Not a focussed energy, but energy nevertheless. Where he finds the time to manage his blog Grasping Reality with Both Hands, I have no idea. In any case, you have to love the subtitle:
The Semi-Journal of Economist J. Bradford DeLong: Fair, Balanced, Reality-Based, and Even-Handed.
You've got to be kidding me, right? Believe me, he may be many things, but he certainly ain't no economist!
O.K., that was supposed to be a joke. But really, does the guy really believe that "fair and balanced" crapola? Can you believe that he really believes this?
Anyway, it should come as no surprise that DeLong loves Krugman almost as much as he loves himself. Here is Brad's review of Krugman's The Accidental Theorist. I quote:
Of all the books of short essays that Paul Krugman has written, I think that this is the very best: you can learn an awful lot of economics from this book, for Krugman's usual clarity and force of argument is raised to a higher power in this book.
Hmmm...well, I'm willing to grant that one may indeed learn a lot of awful economics from Krugman. I'm just kidding (again). I've read many (older) Krugman articles and found them good enough to assign to my classes. The Krugman-Helpman text on trade theory was leading edge. He won his Nobel prize for his work on trade theory, after all.
Precisely how this makes him an authority on macroeconomic theory, I'm not exactly sure. Paul just wants to talk about macro because it's more fun, I guess. I am reminded of when William Vickrey won a Nobel for his work on auction theory. Rather than talk about issues in the area of his expertise, he too spent all his time pontificating on all things macro. Go figure.
Anyway, DeLong tells us that we can learn a lot of economics from Krugman. You will be forgiven for wondering whether DeLong can even tell whether he is learning economics or not. DeLong is, as far as I can tell, an historian. Sometimes he is a good one. Sometimes, he is not so good. But whatever one's view of his abilities as an historian, I have come across no evidence that would lead me to believe that he has any deep understanding of modern macroeconomic theory. I'm not sure how he passed his macro core exam.
This little love affair runs both ways. Here is Krugman "chiding" DeLong (i.e., smacking down Cochrane): Brad DeLong's Foolishness.
It looks as if DeLong was trying to figure out Cochrane's model (have to give him credit for that, at least). But hold on there Brad, Paul says that you shouldn't be doing that: Cochrane has no model to speak of!
Ho boy, this is rich: Paul Krugman complaining that John Cochrane has no model! Since when has Krugman ever let a (serious) model temper or change a prior point of view?
Krugman complains that Cochrane does not understand the "logic" of Keynesian models. Krugman, evidently does understand this logic. This is the same Krugman who called Robert Barro a "bonehead" for not understanding Keynesian logic (see here). That would be the same Robert Barro who, along with Gene Grossman, struggled mightily to formalize the Keynesian logic (Barro-Grossman model, AER 1971). I believe that Barro also serves up the Keynesian model later on in his text (explaining that the issues that arise there are more advanced, hence the reason for why they are saved for later).
Where is the evidence that Paul Krugman has ever thought deeply about the theoretical foundations of Keynesian theory? (Maybe there is some and I have just missed it). As far as I can tell, his "deep" understanding goes no further than an elementary Keynesian cross (OK, OK, maybe he knows a bit more than this).
So, what do I take away from all this? Well, I conclude that it should be clear enough that this dynamic duo are primarily interested in pushing their own pet political agendas; they have no interest in pushing the frontier of economic theory (they apparently know how the world works, so there is evidently nothing left to learn). Nothing wrong with this, of course. They are at their best at calling out the absurdities of some claims made by the "lunatic right." Nothing wrong with this either.
Nothing wrong, that is, except when they label these activities as "fair and balanced" or as "rooted in rigorous theory." That's just plain dishonest.