It is possible, for a responsible state to put in place long-term strategies for fighting violent crime. These would be strategies that work to prevent violent crime in the long term.
One long-term strategy for fighting violent crime is that of putting in place economic policies that ensure that majority of the people have decent opportunities in life.
Another long-term strategy for fighting violent crime is that of putting in place moral training programs that actually work. The ultimate objective should be to create a citizenry that abhors crime just for the sake of it: not folks whose are only motivated by fear of getting arrested or people who are only motivated by fear of being imprisoned. The idea should be to inculcate good morals in people in a positive way: so that people develop a love for doing the right thing.
Yet another long-term strategy for fighting violent crime is that of putting in place an educational system that actually uplifts the people. This should, for one, be an educational system that motivates the people to be dignified, and an educational system that actually enlightens the people. Of course, any ill-placed government will tend to fear such an educational system, for fear of the people getting ‘too enlightened’.