Pursuing the best interests of the child through connecting factors: the case of EU rules on jurisdiction in matters of parental responsibility

The principle of the best interests of the child (BIC) has evolved from a general guideline in international family law to a legally binding standard that permeates European Union private international law (EU PIL). This chapter analyses how the ‘Brussels II system’, as interpreted by the Court of Justice, integrates the BIC principle into its jurisdictional rules in matters of parental responsibility, with particular attention to the role of connecting factors. Traditionally conceived as neutral devices linking a legal situation to a given jurisdiction, connecting factors in EU PIL are increasingly used as normative tools to secure the protection of vulnerable individuals. The discussion first scrutinises the general rule of habitual residence—its normative rationale and its role as the primary gateway to jurisdiction—and then examines the system’s flexibility mechanisms, showing how these devices are designed and/or may be activated only to serve the child’s best interests. The analysis shows that Brussels II system assigns connecting factors on jurisdiction in matters of parental responsibility the protective purpose to secure proximity, continuity and an adequate understanding of the child’s socio-familial environment, by tempering formal rigidity while preserving legal certainty. This axiological turn, however, is effective only to the extent that domestic courts apply the rules purposively and carry out rigorous, BIC-centred reviews.