This introductory chapter provides an overview of the history and nature of international law. Rather than regulating the behaviour of individuals in their relations with one another, international law is usually portrayed as a legal framework to govern the relations between ‘States’, the organized political entities which are the primary subjects of international law. ‘Public international law’ is to be distinguished from ‘private international law’, which describes the principles that determine the applicability of a certain law or set of laws to situations involving individuals with a foreign or transboundary element. Indeed, private international law regulates the conflicts between rules of different domestic legal orders, while public international law concerns relations between States. Today, public international law has exceeded its foundations as the law of inter-State relations and operates as an integral part of the daily lives of individuals.
This chapter studies jurisdiction. The term ‘jurisdiction’ is generally understood by international lawyers as describing the extent, and limits, of the legal competence of a State, entity, or regulatory authority, to make, apply, and enforce legal rules with respect to persons, property, and other matters. Jurisdiction is the necessary corollary to State sovereignty under modern international law, for it represents the exercise of authority of that State in relation to conduct, or to consequences of events, that it deems itself competent to regulate. The quintessential areas of regulation that would be regarded as falling within the domestic jurisdiction of a State include the setting of conditions for the grant of nationality and the conditions under which aliens (non-nationals) may enter a State’s territory. The chapter then distinguishes the types of jurisdiction: prescriptive jurisdiction, enforcement jurisdiction, and adjudicative jurisdiction.
This chapter examines the hierarchy of norms and sources in international law. Establishing a hierarchy of norms and sources allows for a community to elevate certain fundamental principles over ordinary norms, and to establish order and clarity in the relations between norms, authoritative institutions, and legal subjects. In the last half-century, a special class of general rules endowed with peremptory legal force has emerged. Known interchangeably as ‘peremptory norms’ or ‘norms of jus cogens’, these are regarded as possessing a higher status than ordinary rules of international law, and would prevail over the latter in cases of conflict. As such, whether an ordinary rule exists in treaty or customary law, or is a general principle, it is null and void if in conflict with a rule of jus cogens. The chapter also studies a related category known as rights or, more commonly, obligations erga omnes (‘owed to all’).
