As an initial matter, Kennedy identified four principles that undergird the Eighth Amendment's proportionality principle as he understood it. First, "the fixing of prison terms for specific crimes involves a substantive penological judgment that, as a general matter, is properly within the province of legislatures, not courts." Second, the Eighth Amendment does not mandate the adoption of one theory of punishment over another—states are free to tailor their punishments to meet the needs of either a deterrence rationale, a retribution rationale, or both or some other rationale. Third, in light of these first two principles, there is bound to be some variation of punishments between and within particular jurisdictions. Thus, the intra- and interjurisdictional comparison required by the "Solem" test would frequently prove unworkable. Fourth, any proportionality analysis required by the Eighth Amendment should be informed by objective factors to the maximum possible extent.