I believe that sortition is a solution to this. Being a politician should be like jury duty, there's a low but significant probability that you can lose the lottery and have to be a representative for a couple of years. The same mechanism should be uses to select peace officers also. There are certain roles that society appears to need, but that the kind of people who want to fill those roles are likely to be the worst people to do the job (i.e. anyone with a hint of megalomania). Sortition solves this problem.