Words of wisdom:
Civilizations are started by problem solvers. After a time, problem makers start to infest the place. The problem solvers then have to take time away from the civilization and correct the problems the problem makers create. Soon, the problem makers out-number the problem solvers and the roof falls in. This apparently happens over and over throughout history and yet no one has caught on to a simple corrective rule: don't let the problem makers live. If you haven't the stomach for that, then sterilization is a passable substitute.