I’m puzzled by Arnold’s critique of Brad DeLong:

1. The technocrats occasionally make large errors, which tend to persist far longer than market failures.

2. Even when the technocrats are wise, the political process is never going to coincide with DeLong’s fantasy.

Arnold’s right on both points. But how do either undercut Brad’s vision of an “ideal world”? After all:

1. If the alternative to technocrats is populism, then the real question is whether technocratic errors are more persistent than populist errors.

2. Politicians usually ignore wise advice. Is that a reason not to try to make them take wise advice? Brad’s talking about his ideal world; I don’t think he’s claiming that it’s likely to happen. He’d just like to push the real world in his ideal direction.