Dangerously Vague: The Indeterminacy of Dangerousness Criteria of Preventive Sanctions in Dutch Criminal Law

The imposition of preventive sanctions on offenders—ranging from preventive detention to community supervision—generally requires that the offender is held to be “dangerous”: a legal “dangerousness criterion” must be met. This article shows that in Dutch criminal law, these dangerousness criteria are vague. They fail to define, or define in an insufficiently precise way, the type, severity, probability, and time frame of future harm that must be established to fulfill the dangerousness criterion. Drawing on theory on vagueness in law, it is argued that vague dangerousness criteria are undesirable. The vagueness of these criteria renders the decision of whether they are satisfied discretionary. Consequently, courts possess an almost unrestricted power to impose preventive sanctions on offenders. This is incompatible with the rule of law and increases the risk of the overuse of these sanctions. It is therefore advocated that clearer, more precise dangerousness criteria are needed in the Netherlands.