Several commentators in the Polanski thread are apparently taking the view that if a particular exercise of criminal punishment is unlikely to deter crime or rehabilitate the offender, then punishing the offender is pointless at best if not actually barbaric.
Leaving aside the question of whether or not punishing Polanski would deter anyone from committing rape in general or child rape in particular, I find it odd that some people so easily dismiss the idea that Polanski should be punished because he deserves to be punished. One doesn’t have to be a strict Kantian to accept the idea that a person who commits a henious crime should be punished irrespective of whether the punishment specifically deters the offender, or generally deters others from committing similar acts.
For example, I imagine hardly anyone would accept the idea that if Polanski had murdered his victim it would be wrong to punish him unless one could show the punishment was likely to deter murder.
All of which is to say that arguments about how there’s no “point” in punishing Polanski now are only plausible to the extent that it’s accepted that what Polanski did wasn’t a particularly serious crime.