A mostly good (some bad) criticism of Krugman and a bad criticism of Krugman

The good one is the Reinhart and Rogoff response. I think the Herndon, Ash, and Pollin paper was an important contribution to the discussion but I think the criticism of R&R needs to focus on (1.) empirical assumptions they made, (2.) the disproportional focus on the 90% figure that was not the watershed it was purported to be, and (3.) the monotone public discussion of the direction of causality (which has not matched their writing on the subject). These are three valid areas of criticism of R&R, the last one especially. Krugman's gone substantially beyond these criticisms (although he's regularly pointed out how good Rogoff's work is). The worst is when Krugman treats them like eager accomplices of politicians that support austerity, like they've been hiding data, or that the debate has turned on their paper. The last one may only be rhetorical flourish (it's pretty absurd), but it's still unfair to R&R. Reinhart and Rogoff have addressed each of these in their letter.

It does get goofy in parts, though. Take this:

"Your recent April 29, 2013 NY Times blog The Italian Miracle is meant to highlight how in high-debt Italy, interest rates have come down since the European Central Bank’s well-placed efforts to act more as a lender of last resort to periphery countries. No disagreement there. However, this positive development is meant to re-enforce your strongly held view that high debt is not a problem (even for Italy) and that causality runs exclusively from slow growth to debt... Indeed, your repeatedly-expressed view that slow growth causes high debt but not visa-versa, is hardly supported by the recent literature on the subject... Of course, it is well known that the economic cycle impacts government finances and therefore debt (causation from growth to debt). Cyclically adjusted budgets have been around for decades, your shallow characterization of the growth-debt connection." [emphasis is mine]

It's stuff like this that makes it hard for an objective reader to take them seriously. This obviously has nothing at all to do with Krugman's position - he's never said causality runs exclusively from slow growth to debt. He's gone out of his way to present the alternative. This is common across people that go nuts over Krugman -  straw-manning comes with the territory in blogs, but Krugman gets more straw-manning than almost any other economist on the internet right now.

The bad criticism is from Scott Sumner and really isn't worth saying much about. He gets worked up that there are things Krugman doesn't like about conservative narratives and concludes that Krugman thinks that it describes all conservatives to a tee (when he actually names alternatives in the post and complains about conservatives disowning them!). Anyway, I really don't want to draw more attention to Scott Sumner. I'm not even sure his blog is going to survive my transition out of Google Reader. But I did want to highlight the post for these two responses from Aidan (who comments here too sometimes):

This:

"I actually have no idea what issue you have with Krugman’s piece, as you seem to agree with the individual points he raises in a way that today’s Republican Party does not. Are you confusing right-leaning economists with the right in general? Yes, some conservative intellectuals believe in anthropomorphic climate, expansionary monetary policy in a recession, etc., but they are so noteworthy that there are features written about the fact that they exist. Are there any prominent conservative politicians that hold these views? Any influential members of the conservative movement?"

But ESPECIALLY this (which is a point I make a lot too):

"I think it’d be a much better use of your time if you spent half the energy you spend bickering with Keynesians who are roughly in full agreement about our current monetary policy needs on trying to convince prominent conservative politicians and thinkers that their views on inflation and monetary easing are dangerous and wrong. Krugman wrote that spending too much time focusing on his differences with MMT is a waste of time because those disagreements aren’t particularly important right now. I think it’s similarly more important that you spend more time focusing on the people who are loudly and actively opposed to monetary easing. I’ll give you a hint: they aren’t the Keynesians!"

Why is there so little high quality critiques of Krugman out there and so much crap? Maybe the question answers itself. Actually the best place for high quality Krugman criticism is Bob Murphy, but this may just be the law of large numbers (if you figure 95% of his criticism misses the mark given the volume of it of course you're going to get some really piercing critiques every couple of weeks). Krugmania is one of the weirdest things in the economics blogosphere, IMO. I don't know why people don't just say "well he gets a little liberal and a little shrill for me sometimes and I don't like that" and leave it at that. Instead they put out some really nutty criticisms.