Refine laws on stings

I read numerous articles on sting operations - they are growing to meet statistics on how many criminals are arrested. In a number of cases they are setting up the sting where it is a very fine line between enticement and not. They prey on certain profiles where left alone, they may have never become a criminal. We have the highest incarcerated population in the country. I am asking that laws be created where sting operations can only be set up on existing criminals. This ensures that the person has truly committed a crime at least once and not be convicted and imprisoned on a hypothetical crime. Law enforcement has gotten extremely good at the enticement game.