In private markets for goods, say the market for cars, if I think that a car is a fantastic car. And we would find pretty soon that it didn't meet our desires very effectively. So really stupid policies should be rooted out and voters should learn that these policies that you claim economists know more about than they do actually don't work. The key thing is that you have to understand what are politicians competing about.
Bryan Caplan, of George Mason University and blogger at EconLog, talks about his book, The Myth of the Rational Voter: Why Democracies Choose Bad Policies. Caplan argues that democracies work well in giving voters what they want but unfortunately, what voters want isn't particularly wise, especially when it comes to economic policy. He outlines a series of systematic biases we often have on economic topics and explains why we have little or no incentive to improve our understanding of the world and vote wisely. So, it's not special interests that are messing things up but the very incentives that lie at the heart of a vote-based system. This is a disturbing and provocative lens for viewing political outcomes.