The legal proceeding and judgement are the proofs and the declaration that a criminal has broken the social treaty, and consequently that he is no longer a member of the state.
Gist of Idea
A trial proves that a criminal has broken the social treaty, and is no longer a member of the state
Jean-Jacques Rousseau (The Social Contract (tr Cress) , II.05)
This seems to be a plausible rationalisation of capital punishment, but what about lesser crimes. Is the interior of a prison a sort of temporary exile from the state? Hence the significance of whether prisoners are allowed to vote. But 19811.
Rousseau,Jean-Jacques: 'The Basic Political Writings', ed/tr. Cress,Donald A. [Hackett 1987], p.159
Idea 19811 Only people who are actually dangerous should be executed, even as an example [Rousseau]