One indicator could be the fact that every answer he has in his debates is that campaign funding needs to be reformed. No matter what question he is asked, that is his answer. He is also mentally unstable when he thinks that our country should be like the failed system of the USSR where he had his honeymoon. Doing his honeymoon in the old USSR is enough to convince anyone that the guy is not right in the head. But, don't worry about Sanders. This all revolves around the Clintons. The corrupt element of politics.