From blame to punishment
On the axis: Moral responsibility · deserved punishment
If no one deserves at bottom, retribution collapses, but is it to be mourned? Protecting, deterring, and repairing may suffice to ground punishment, without ever speaking of a debt.
Justification
Punishment is demanded by justice itself, as retribution proportionate to the crime (juridical law of retaliation), never as a mere means of social utility: punishing someone to deter others would treat him as a means. This is classical retributivism.
Metaphysics of Morals, Doctrine of Right, §49 E
Justification
Punishment is in itself an evil, a pain, and is justified only by the utility it yields: all punishment in itself is evil; upon the principle of utility, if it ought at all to be admitted, it ought only to be admitted in as far as it promises to exclude some greater evil. Its first end is the prevention of offences, chiefly by deterrence and secondarily by the reform of the offender; Bentham explicitly rejects retribution and the lex talionis as an evil added to an evil, with no profit.
All punishment in itself is evil. Upon the principle of utility, if it ought at all to be admitted, it ought only to be admitted in as far as it promises to exclude some greater evil.An Introduction to the Principles of Morals and Legislation, ch. XIII, §2
An Introduction to the Principles of Morals and Legislation, ch. XIII-XIV (punishment, its ends and its measure)
leads to: The meaning of punishment (Do we deserve our punishment?)