Customary International Law: A New Theory with Practical Applications

440 Pages·2011·2.3 MB·English

by  Brian D. Lepard

customaryinternationallaw
Customaryinternationallaw,althoughlongrecognizedasaprimarysourceofinter-
national law, remains replete with enigmas, both conceptual and practical. These
includehowtodeterminetheexistenceofopiniojuris,thefunctionofthestateprac-
ticerequirement,thedefinitionofjuscogenscustomarynorms,andtherelationship
between customary international law and ethics. In part because of these enigmas,
thesubjecthasgeneratedawide-rangingliterature.However,norecentbook-length
workhasattemptedtoarticulateacomprehensivetheoryofcustomaryinternational
lawthatcaneffectivelyresolvethesequestions.
Thisbooksetsouttoaccomplishthisgoal.Itsapproachisuniqueinanumberof
ways.Forexample,itismultidisciplinaryanddrawsinsightsfromfieldssuchaslegal
theory,philosophy,politicalscience,andgametheory.Inaddition,itisanchoredina
sophisticatedethicalframeworkandexploresatlengththeinterconnectionsbetween
customaryinternationallawandethics.
Brian D. Lepard is Law Alumni Professor of Law at the University of Nebraska
CollegeofLawandcodirectoroftheuniversity’sHumanRightsandHumanDiversity
Initiative. Professor Lepard has served as Chair of the International Legal Theory
InterestGroupoftheAmericanSocietyofInternationalLaw.HisbooksincludeHope
for a Global Ethic: Shared Principles in Religious Scriptures (2005) and Rethinking
Humanitarian Intervention: A Fresh Legal Approach Based on Fundamental Ethical
PrinciplesinInternationalLawandWorldReligions(2002).Hisarticleshaveappeared
in such journals as the Duke Journal of Comparative & International Law and the
JournalofHumanRights.

ASILStudiesinInternationalLegalTheory
SeriesEditors:
MortimerN.S.Seller,UniversityofBaltimore
ElizabethAndersen,AmericanSocietyofInternationalLaw
ThepurposeoftheASILStudiesinInternationalLegalTheoryistoclarifyandimprove
thetheoreticalfoundationsofinternationallaw.Toooftentheprogressivedevelop-
ment and implementation of international law has foundered on confusion about
firstprinciples.Thisserieswillraisethelevelofpublicandscholarlydiscussionabout
thestructureandpurposesoftheworldlegalorderandhowbesttoachieveglobal
justicethroughlaw.
The idea for this series grows out of the International Legal Theory project of
theAmericanSocietyofInternationalLaw.ThebookseriesASILStudiesinInterna-
tional Legal Theory will deepen this exchange by publishing scholarly monographs
andeditedvolumesofessaysconsideringsubjectsininternationallegaltheory.
EditorialBoard
SamanthaBesson,UniversityofFribourg
AllenBuchanan,DukeUniversity
DavidKennedy,HarvardUniversity
JanKlabbers,UniversityofHelsinki
LarryMay,VanderbiltUniversity
HelenStacy,StanfordUniversity
JohnTasioulas,OxfordUniversity
FernandoTeson,FloridaStateUniversity
OnumaYasuak,UniversityofTokyo

Customary International Law
a new theory with practical applications
BRIAND.LEPARD
UniversityofNebraska
cambridgeuniversitypress
Cambridge,NewYork,Melbourne,Madrid,CapeTown,Singapore,
Sa˜oPaulo,Delhi,Dubai,Tokyo
CambridgeUniversityPress
32AvenueoftheAmericas,NewYork,ny10013-2473,usa
www.cambridge.org
Informationonthistitle:www.cambridge.org/9780521138727
(cid:1)c BrianD.Lepard2010
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithoutthewritten
permissionofCambridgeUniversityPress.
Firstpublished2010
PrintedintheUnitedStatesofAmerica
AcatalogrecordforthispublicationisavailablefromtheBritishLibrary.
LibraryofCongressCataloginginPublicationdata
Lepard,BrianD.
Customaryinternationallaw:anewtheorywithpracticalapplications/
BrianD.Lepard.
p. cm.
Includesbibliographicalreferencesandindex.
isbn978-0-521-19136-4(hardback)–isbn978-0-521-13872-7(pbk.)
1.Customarylaw,International. I.Title.
kz1277.l47 2010
341–dc22 2009026767
isbn978-0-521-19136-4Hardback
isbn978-0-521-13872-7Paperback
CambridgeUniversityPresshasnoresponsibilityforthepersistenceor
accuracyofurlsforexternalorthird-partyInternetWebsitesreferredtoin
thispublicationanddoesnotguaranteethatanycontentonsuchWebsitesis,
orwillremain,accurateorappropriate.
ForJenina

Contents
Figures pagexi
Acknowledgments xiii
Cases xv
partone: theenigmasofcustomaryinternationallaw
1. TheNeedforaNewTheory 3
2. SomeConceptualEnigmas 14
3. SomePracticalEnigmas 30
parttwo: foundationsofanewtheoryofcustomary
internationallaw
4. ClarifyingtheConceptofAuthoritativeInternationalLegalNorms 47
5. FundamentalEthicalPrinciplesandCustomaryInternationalLaw 77
partthree: resolvingtheconceptualenigmasof
customaryinternationallaw
6. TowardaNewNormativeTheoryofCustomaryInternationalLaw 97
7. ANewUnderstandingofOpinioJuris 112
8. TheFunctionoftheStatePracticeRequirement 122
9. EthicsandCustomaryInternationalLaw 140
10. DemocraticPrinciplesandCustomaryInternationalLaw 151
11. TheRelationshipBetweenCustomaryInternationalLawand
GeneralPrinciplesofLaw 162
ix