Christopher Lewis (Harvard Law School; Harvard Society of Fellows) has posted Unlocking Lex Talionis on SSRN. Here is the abstract:
In this paper, I operationalize the classical retributive formulation of proportionality—Lex Talionis, or "an eye for an eye"—to give some conservative estimates of what it might entail as a limit on the severity of permissible punishment. Respecting Lex Talionis would entail a radically lenient transformation of the criminal legal systems of the United States (and many other countries), reducing incarceration for non-homicide offenses by at least an order of magnitude.
Very interesting and recommended.