Jails may fill up with criminals, but killing them off isn't the right way to go about solving that. After all, they are still human beings and still have human dignity. There are very few things they can do, if any, that can take that away, and regardless, we should still try to rehabilitate over kill them. Maybe just my opinion, but I think it makes sense. We need to find the real source of the lack of morality and strike there, not just kill those who disobey. Then the government gets in danger of ruling simply by sword, as they would only keep people in check by threatening them with pain and death, and that could lead to all kinds of nasty things.