Abstract
This chapter briefly looks at the nature of sovereignty and its parameters in international law, but essentially focuses on the function and nature of jurisdiction. It first examines the breadth of the space in which sovereignty is exercised; namely, land, sea, and air. Thereafter, it assesses territorial jurisdiction (in both its objective and subjective dimensions) and examines the practice of the four extraterritorial principles of jurisdiction; namely, nationality-based, the protective principle, passive personality, and universal jurisdiction. The chapter then considers instances where national courts refuse to exercise their ordinary jurisdiction, namely, instances where the accused is covered by the privilege of immunity or because his or her arrest was illegal. Finally, it looks at the US practice of extraterritorial jurisdiction, whereby sometimes the sovereignty of other nations has been breached.