I can name one engineer who was president, Jimmy Carter. How many politicians in general are engineers or scientists? How many are in positions Sam mentions? My guess would be < 10%. I'm probably overestimating. Engineers are probably one of the most if not the most under represented in the field of politics. I can name a few doctors who are candidates or successful politicians.

Engineers can be politicians, would be the name of my non-profit. This new yorker piece is also a good read: http://www.newyorker.com/tech/elements/two-nasa-engineers-tr...