Paul Krugman declines to debate with Klein

Yesterday Paul Krugman wrote how highly he thinks of Ezra Klein (I do to). Today he criticizes someone or other who is well meaning but confused.

a variety of people, some of them well-intentioned, arguing that while sure, inequality is an issue, the crucial thing now is to get the economy growing and create more jobs; these people will argue that populism is a diversion from the main issue.

Who does he have in mind ? Jon Chait caught Paul Krugman not at all debating David Brooks.