That would be a good hypothesis if politicians wouldn't be constantly being caught lying, cheating and breaking promises, starting wars or saving bankrupt industries with people's money. But since they do that, with little consequences, the theory that they are actually good at getting what they want without paying the cost we would pay for something far smaller seems more likely.
That's a good point :) But they are breaking laws in the process. God, the US government is even breaking the habeas corpus, the most important law of all, and nobody bats an eye.
So do I. There is a selection process. It is not selecting for non-criminality. It isn't selecting for criminality necessarily either, but it certainly is not strongly selecting against, in the sense intended.