I just read an article that I think is the best explanation of statist arrogance I've come across. It's background is two essays; one by Mises on why socialists can't calculate and the other by Hayek on the pretense of knowledge. This article is short and easy to understand. It uses Obama as the example but it applies to all who would know best.

It also contains a great Rothbard quote, "It is no crime to be ignorant of economics, which is, after all, a specialized discipline and one that most people consider to be a 'dismal science.' But it is totally irresponsible to have a loud and vociferous opinion on economic subjects while remaining in this state of ignorance."