  It is worth distinguishing between two versions of this view. According to Moore, all culpable wrongdoers incur a duty to allow themselves to suffer.    Retributive justice  is done when punishment imposes that suffering, and this is what justifies the imposition of criminal punishment (Moore 1997, 70–71). Moore argues that the suffering of culpable wrongdoers is intrinsically good. On a rival view, suffering is always intrinsically bad. We must accept, however, that in some cases not all suffering can be avoided. Sometimes we must choose between wrongdoers suffering now and others suffering at the hands of wrongdoers later. Only by imposing the former can we protect against the latter. It might look as though punishing wrongdoers for these protective reasons amounts to treating them as mere means. But this is not necessarily so. Tadros argues that some wrongdoers incur duties to protect others at the cost of some harm to themselves. We can justify imposing punishments that come at this cost to these wrongdoers, when the punishments protect others by preventing future wrongs. As those punished are only doing their duty, we can reasonably claim that they are not treated as mere means (Tadros 2011c; 2016). Though Moore and Tadros disagree on many things, their views also have something in common. Both claim that, as a matter of principle, anyone might impose punishment that discharges wrongdoers’ secondary duties. The value to which both appeal to justify punishment is impersonal: it is neither relational nor essentially public (Moore 2009a, 42; Tadros 2011c, 293).