The expansion of treaty-based extraterritorial criminal jurisdiction

This chapter aims to provide the comprehensive and systematic examination of treaty-based extraterritorial jurisdiction that has been noticeably lacking in scholarship during the last century. The chapter is empirical: it is informed by a worldwide survey of treaty practice, stretching from 1937 to 2017, including the examination of corresponding preparatory works and official commentaries and the implementation of treaty law in subsequent State practice. Informed by a wealth of primary data sources, this chapter makes several new and important contributions to the field. In particular, it shows that since the period of the League of Nations, treaty-based extraterritorial jurisdiction has been persistently, if quietly and incoherently, expanding over that time in a number of discernible dimensions. Moreover, extraterritorial jurisdiction in treaty-making is established independent of rules of customary international law on extraterritorial jurisdiction. The categories of jurisdiction in treaty form may be distinguished from customary rules on extraterritorial jurisdiction in important respects.