Persons who are dangerous and legally responsible, but who have not yet committed any currently recognised criminal offence, fall within the gap left between the domains of criminal justice and civil commitment. Many jurisdictions operate legal regimes that permit the detention of such persons in order to prevent the occurrence of anticipated criminal harms. These regimes often either fail to respect the principle of proportionality or contradictorily treat a dangerous offender as both legally responsible and not responsible at the same (...) time. In response to these problems, a number of preventive detention models have been proposed. Retributivist models seek to prevent the occurrence of anticipated criminal harms by requiring blame on the dangerous person’s part in order to warrant detention. However, these models are ill-equipped to deal with the problem of coextensiveness; i.e., they struggle to comprehensively reconcile proportionality in punitive sentencing with the period over which dangerous persons remain dangerous and during which one might therefore want them to be incapacitated. In order to achieve comprehensive incapacitation of dangerous persons for the duration of their dangerousness, retributivist models are forced to abandon their fidelity to proportionality in punitive sentencing, thereby losing themselves in the process. Accordingly, if the practice of preventive detention can be justified at all, such justification will not be of a retributivist character. (shrink)