Freedom, Security and Proportionality: A Comparative and Constitutional Perspective on Preventive Detention in Dutch Criminal Law

The oldest and most severe security measure in Dutch criminal law is the terbeschikkingstelling (TBS), or "placement at the disposal of the government." The indeterminate tbs order (ongemaximeerde terbeschikkingstelling met dwangverpleging), involves involuntary treatment for dangerous offenders with a mental disorder at the time of their crime. Its primary aim is to protect society by reducing the risk of recidivism. However, due to its indeterminate nature and inherent deprivation of liberty, this measure profoundly infringes on the offender's right to freedom. Significant challenges exist within the current legal framework regarding TBS, particularly regarding legal certainty and consistency. For instance, the requirement to establish a mental disorder is interpreted inconsistently, with case law varying between accepting plausibility (aannemelijkheid) and requiring proof beyond a reasonable doubt (buiten redelijke twijfel), which is a much higher standard. Similarly, the criterion of dangerousness, which justifies imposing tbs for societal safety, lacks clear legal definition. The law and practice provide little guidance on what constitutes "dangerousness" or the level of certainty needed to establish the required risk of reoffending. The dissertation begins with an in-depth analysis of the currents legal framework governing TBS, specifically Articles 37a to 38e of the Dutch Criminal Code. It also examines related sanctions in Dutch law, such as life imprisonment, the measure for temporary detention of repeat offenders (ISD), and the behavioral influence and freedom-restricting measure (GVM). The research extends to an analysis of civil detention under the Wet verplichte geestelijke gezondheidszorg (Compulsory Mental Health Care Act) and the Wet zorg en dwang (Care and Coercion Act), exploring their intersections with TBS. To contextualize the regulation of TBS, a comparative analysis with German criminal law is provided. Germany’s system includes two measures comparable to the Dutch indeterminate TBS order: placement in a psychiatric hospital (Unterbringung in einem psychiatrischen Krankenhaus) and preventive detention (Sicherungsverwahrung). These measures are regulated by Germany's constitutional principle of proportionality (Verhältnismäßigkeitsgrundsatz), requiring a careful balance between individual rights and public safety. The dissertation also examines the right to liberty under Article 5 of the European Convention on Human Rights (ECHR), which permits deprivation of liberty only if it is necessary and proportional. It explores proportionality as a fundamental public law principle that mandates state actions to be suitable, necessary, and justified by balancing individual and societal interests. Ultimately, the research argues for a revision of the regulation of the indeterminate tbs order, proposing that proportionality should play a more central role. By embedding proportionality more explicitly in the legal framework, the regulation of tbs can better balance fundamental rights with societal safety, ensuring greater legal certainty and fairness in its application.