The incorporation of custom

• Author: Gib van Ert
• Pages: 236-283

6 he incorporation of

custom

By the doctrine of incorporation, rules of customar y international

law can be recognized and enforced by the judiciary as domestic law

without the need for legislative implementation. Eighteenth- a nd nine-

teenth-century Eng lish authorities frequently depicted the l aw of na-

tions – meaning customa ry rather than conventional internat ional law

– as forming part of the common law. e Supreme Court of Canada

has armed the common law’s adoption of customary international

law in this way, while also recog nizing certain limits on t he doctrine.

e principle of respect for internationa l law is given its freest reign

in this area of the reception system. e incorporation doctrine invites

courts not only to adjudicate consistently with international law but to

adopt international custom as t he rules upon which their adjudication is

based. For the reception system so wholly to embrace custom by means

of the common law is not only in keeping with t he principle of respect for

international law but is al so consistent with the principle of self-govern-

ment. For the common law is always susceptible to abolition or curtail-

ment by statute. To permit custom to be incorporated by the common

law is to subject it to the exercise of sel f-government through legislative

action. Here is an instance of the reception system balancing its prin-

ciples: Respect for international law is made the law’s default position

but subject to rejection or amendment in keeping w ith self-government.

6.1 Case law on the incorporation doctrine

e incorporation of custom is a theme much less frequently considered

by Canadian courts than the other leading features of the reception

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 • The incorporation of c ustom

237

system, namely the treat y implementation requirement, the presump-

tion of conformity with international law, legislative sovereignt y to

violate international l aw, and perhaps even the judicial notice of inter-

national norms. e predict able result is that the doctr ine’s operation,

and even its nature, are less developed than they might be. But the

doctrine’s continued existence in Ca nadian law is clear.

(a) e English inheritance

e applicability of cu stomary international law in Engli sh law was es-

tablished in the eighteenth centu ry. In Buvot v Barbuit ( ), Lord Ta l-

bot is said to have declared that “the law of nations, to its full extent,

was part of the law of Engl and.” Nearly  years later, in Tri que t v Bath

(), Lord Manseld CJ (who appeared as cou nsel before Lord Talbot

in Buvot) armed and relied upon Lord Talbot’s dictum. Appearing as

counsel before Lord Manseld was Wi lliam Blackstone, who expla ined

in his Commentarie s () that “the law of nations . . . is here adopted

in it’s [sic] full extent by the common law, and is held to be a part of the

law of the land.” Shortly thereafter, in Heatheld v Chilton (), Lord

Manseld declared that the law of nations is “part of the common law

of England” and that “the law of nations will be carried as far in Eng-

land, as a ny where.”

In Novello v Toogood (), Abbot CJ held that the Act of Parlia-

ment before him “must . . . be construed according to the common law,

of which the law of nations must be deemed a par t.” In De Wutz v Hen-

dricks (), Best CJ described the law of nations as “in all cases . . .

adopted into the municipal code of every civilized countr y.” e unity

of customary international law and the common law was armed by

Lord Langdale MR in Duke of Brunswick v e King of Hanover (),

who declared that “the law of nations . . . when ascertained, is to be

deemed part of the common law of England.” By , this doctrine

 () Cas T Talb ,  ER  .

 ()  Burr  at  –,  ER  at  –.

 Sir Will iam Blackstone, Commenta ries on the Laws of England, vol  (Chic ago:

University of Ch icago Press: ) [Blackstone] at .

 ()  Burr  [Heatheld] at ,  ER  at .

 Novello v Toogood (),  B & C  at ,  ER   at .

 De Wutz v Hendricks ( ),  Bing  at –,  ER  at .

 Duke of Brunsw ick v e King of Hanover (),  Beav  [Du ke of Brunswick] at

,  ER  at .

Using International Law in Canadian Courts

238

was so well established that Sir John Stuart VC observed t hat it was

supported by “unquestioned authority.”

e clarity of t he incorporation doctrine in English law was u nder-

mined somewhat in the dicult case of R v Keyn (e Franconia). e

defendant was charged w ith manslaughter in the death of a Briton fol-

lowing a collision at sea. He argued that England lacked jurisdiction

because at common law the realm ends at low-water ma rk and all else is

high seas. At customary international law, however, the adjacent wat-

ers in which the cr ime took place were recognized as within Br itish ter-

ritory. e majority held for the defendant. Lord Cockbur n CJ rejected

the argument that rules of customary international law could entitle

or oblige the court to exercise jur isdiction. Nor would unanimous state

practice suce to make such a l aw binding on England. Only an Act of

Parliament would do to indicate the countr y’s assent to be bound by a

new international law. For a court to apply such a law w ithout an Act of

Parliament would be to usurp the province of the legislature. “e as-

sent of nations is doubtless sucient to give the power of parliament-

ary legisl ation in a matter otherwise with in the sphere of international

law; but it would be powerless to confer without such legislation a jur is-

diction beyond and unknow n to the law, such as that now insisted on,

a jurisdiction over foreigners in foreign ships on a portion of the high

sea s.” I suggest later that the result in Keyn can be explained within

the doctrine of incorporation as turning on the distinction between

permissive and ma ndatory customary international l aw.

e place of customary international law in domestic law arose

again in West Rand Central Gold Mining v e King. is was a petition

of right brought by an English company for recovery f rom the UK gov-

ernment of an amount of gold taken from it by ocia ls of the South

African Republic prior to that state’s conquest and annexation by the

UK in the Boer War. e suppliants’ argu ment was in three parts: () by

international law, the sovereign of a conquering state is liable for the

obligations of the conquered; () international law forms part of the

 Emperor of Austr ia v Day and Kossuth (),  Gi  [Emperor of Aust ria] at ,

 ER  at .

 ()  Ex D  (Eng Ct C rown of Cases Reser ved) [Keyn].

 Ibid at –.

 See Section .(b), below, in th is chapter.

 []  KB  (Eng Div Ct).