Introduction: Nature and Origins of Public International Law

• Author: John H. Currie
• Pages: 1-20

1

CHAPTER 1

INTRODUCTION:

NATURE AND

ORIGINS OF PUBLIC

INTERNATIONAL LAW

A. NATURE OF PUBLIC INTERNATIONAL LAW

1) General Character and Distinction from National Law

Public international law is not so much an area or topic of the law as it

is an entire legal system that is conceptually distinct from the national

legal systems that regulate daily life within states. It comprises a whole

set of formal rules and customary practices that together def‌ine the

legal rights and obligations, and govern the interactions, of internation-

al legal subjects. Traditionally, only states have enjoyed the status of

international legal subjects and as we shall see this is still largely the

case today.1 This explains the term “international law,” which of course

denotes “law between nations.”2 It is also why international law is often

described as the “law of nations.”3

Thus, public international law exists outside of and apart from na-

tional legal systems.4It may be useful to think of it as a legal system that

1 But see furthe r Chapter 2, where we explore in great er depth the modern di-

mensions of inter national legal person ality.

2 See J. Bentham , An Introduction to the Principles of Morals an d Legislation, 1789

(London: W. Pickering, 1823), c. XVII at para. 2.

3 See H. Grotius, Three Books Treating of the Rights of War and Peace, Book I: Of

the Rights of Peace and War,1625 (London: M.W. for Thomas Basset, 1682) at 5

[Three Books].

4 This is not meant to s uggest that internat ional and national legal sy stems do not

interact, nor to prejudge t he nature of their relation ship. In fact, they intersect

PUBLIC INTERNATIONA L LAW2

applies where national legal systems leave off: while the latter govern

relations of persons within states, international law essentially governs

relations between states themselves. Moreover, unlike the multiplicity

of national legal systems that exist worldwide, there is one universally

applicable international legal system regulating the entire international

community.5

International lawyers and judges use a variety of terms to describe

national law, the most common of which are “domestic,” “internal,”

or “municipal” law. All of these are meant to emphasize its distinct

character when juxtaposed with international law. As a concrete ex-

ample, the entire Canadian legal system (including the Canadian Con-

stitution; all federal, provincial, and municipal laws and regulations;

the common law; and all Canadian legal structures and institutions)

would be described by international lawyers as a national (or “domes-

tic,” “internal,” or “municipal”) legal system. So too would the Russian

or Costa Rican legal systems, for example. In contrast, the law govern-

ing Canada’s relationship with Russia or Costa Rica or any other state

would be described as international law.

As we shall see further below, the substantive scope of internation-

al law has grown since the mid-twentieth century to include many sub-

ject-areas that traditionally were considered to be of concern only to

domestic legal systems.6 Along with this substantive expansion have

come new players in the international legal system, some — for instance,

the United Nations and other international organizations — with for-

mal capacities within that system, and others — such as individuals

and non-governmental organizations — with more limited or informal

roles.7 As a result, it is no longer accurate to think of international

law solely in terms of the mutual legal rights and obligations of states.

Rather, it now includes rules and mechanisms governing the relations

of states, international organizations and, in a limited number of areas

of concern to the international community generally, individuals and

in many ways (see, for ex ample, Chapter 3, Section C(4), as well a s Chapters 6,

8, and 9) but are nevertheles s generally considered to be di stinct systems.

5 Although it should be noted t hat within that sy stem are a number of regional

sub-system s focused on particul ar areas of internation al law of particular i nter-

est to certa in groupings of states: see, for ex ample, Chapter 5, Section D and

Chapter 10, Section C. Such reg ional sub-systems ar e built, however, on the

common substrat um of the universally applic able international legal s ystem.

6 The most prominent exa mple of this is probably the advent of inte rnational hu-

man right s law: see Chapter 10.

7 We explore the intern ational legal personal ity of various players in th e inter-

national lega l system below in Chapter 2.