Matthew E. Kahn writes,

If economists would be such a useful addition to Congress as we remind our colleagues that there are “no free lunches” and that all actions have unintended consequences, why have we made so few inroads here? Is it supply or demand? Do voters not like us because we are loud and arrogant? Are we too gutless to stomach the long campaign? Does academic economics self select people who are “unelectable”? If there was campaign reform such that politicians debated each other on PBS, people watched the televised debates and then voted, would more economists try?

I think that a lot of what economists do is tell people what they do not want to hear. For example, they do not want to hear that when the price of gasoline goes up, the market is telling them that they should drive less. They want to hear instead that the evil oil companies have developed a sudden outbreak of greed.

Telling people what they do not want to hear and getting elected to office are two very distinct jobs.