Negative retributivism is the view that though the primary justifying aim of legal punishment is the reduction of crime, the state's efforts to do so are subject to side-constraints that forbid punishment of the innocent and disproportionate punishment of the guilty. I contend that insufficient attention has been paid to what the side-constraints commit us to in constructing a theory of legal punishment, even one primarily oriented toward reducing crime. Specifically, I argue that the side-constraints limit the kinds of actions that are appropriately criminalised, the kinds of beings who are appropriately liable to legal punishment, and the absolute and comparative severity of sanctions. I also argue that a third retributive constraint is needed, one which I term a ‘non-degradation constraint’. According to this third constraint, in our efforts to reduce crime, we must avoid treating offenders as non-moral beings and ensure that punishment does not atrophy or erode the complex capacity for moral responsibility. When this third constraint is combined with the persuasive instrumental case for promoting the moral responsiveness of offenders, the result is an approach to crime reduction that is quite different from ones which emphasise general deterrence and incapacitation. In the closing section, I broach the question whether negative retributivism has been appropriately characterised in the literature on legal punishment.