If all 2 million people in prison in the US are violent criminals, then there's a _really_ big problem.
Clearly it's better to stop people from becoming violent criminals, then to wait (or push them, e.g. by increasing income inequality, reducing respect for "unskilled" professions, etc.) for them to become violent criminals and then punish them.
Clearly it's better to stop people from becoming violent criminals, then to wait (or push them, e.g. by increasing income inequality, reducing respect for "unskilled" professions, etc.) for them to become violent criminals and then punish them.