"Expert Political Judgement: How good is it? how can we know?", Philip Tetlock shows how experts are no better than average in their predictions. This is a corollary of the findings from "The Wisdom of Crowds" which shows how large groups of independent people, when their views are averaged, can provide better predictions than professed experts, and very accurate estimates of the weight of an ox or the number of sweets in a jar!
Maybe this is one reason why we should involve more people in political decision making.