Government 1740Government 1740

Lecture 4: Sources of International Law:

Custom and Treaties

INTERNATIONAL LAWINTERNATIONAL LAW Summer 2006

OUTLINEOUTLINEI. Sources of International LawII. Customary International Law (CIL)

A. What it isB. Theories critical of CIL

II. The Nature of Treaty ObligationsA. DefinitionB. Pacta Sunt ServandaC. The Vienna ConventionD. Invalid Treaties

III. How Treaties are Made: From Negotiation to Interpretation

IV. Treaty Termination: cooperatively, unilaterally, and exceptional circumstances

I. Sources of International I. Sources of International LawLaw

Article 38 of the International Court of Justice:

•Treaties•Custom•General Principles of Law•Judicial Decisions•Writings of Jurists

•What constitutes custom?•Broad acceptance, regularity, duration of a practice•Opinio juris

•Why is custom is binding?

•The contestation of custom – critics?

Customary International Customary International LawLaw

The “Traditional View”The “Traditional View”•Rules that evolve from state practice

Theories Critical of Theories Critical of Customary Customary

International LawInternational LawNormative critique: weakly linked with consent.

Positive critique:– CIL does not explain foreign policies or world

politics.– It only reflects the interests and practices of the

most powerful

environment interests behavior

Other sources of Other sources of International LawInternational Law

General Principles of law

•Judicial Decisions

•Writings of Jurists

II. The Nature of Treaty II. The Nature of Treaty ObligationsObligations

Treaty: An international agreement between two or more subjects of international law which is intended to create rights and obligations for the parties to it

Basic Principles of Treaty Basic Principles of Treaty LawLaw

Pacta Sunt Servanda: Agreements must be served; they are binding

1969 Vienna Convention on the Law of Treaties

Invalid TreatiesInvalid TreatiesUnauthorized negotiatorEssential error of factImpose obligations on third parties

Invalid TreatiesInvalid TreatiesAgainst prevailing norms or illegal

Invalid Treaties?Invalid Treaties?Concluded under the threat or use of force

(VCLT Article 52)

Opium Wars

Treaty of Nanking

Invalid Invalid Treaties?Treaties?

Concluded under the threat or use of force

Treaty of Versailles

Invalid Treaties?Invalid Treaties?

Concluded under the threat or use of force

Guantanamo Bay

III. How Treaties are III. How Treaties are MadeMade

Negotiation– All treaties begin with politics– Shaped by power, interests,

bargaining, and persuasion.

Treatymaking, Treatymaking, continued...continued...

Signature: signing of adopted text

Adoption: agreement on a final text

Ratification: done by the executive of each country, according to domestic rules that typically involve the legislature

“...the exclusion or modification of the legal effect of certain treaty provisions.”

Reservations:Reservations:

ICCPR Reservations:ICCPR Reservations:United States:

"(2) That the United States reserves the right, subject to its Constitutional constraints, to impose capital punishment on any person (other than a pregnant woman) duly convicted under existing or future laws permitting the imposition of capital punishment, including such punishment for crimes committed by persons below eighteen years of age.”

Other Aspects of Treaty-makingOther Aspects of Treaty-making

•Accession/Adhesion

•Entry Into Force

•Interpretation

IV. Treaty TerminationIV. Treaty Termination•Terms of the Treaty itself

•Notice

•Explicit or Tacit Agreement

•Violation by one side

•Clausula rebus sic stantibus

•State Extinction

Summary:Summary: Treaties are the most important source of

international law, followed by custom Custom requires a pattern of behavior, as well as a

widespread belief that a norm is obligatory (opinio juris)

Pacta sunt Servanda: Treaties are to be observed Secondary rules have developed on Treaty Law:

Vienna Convention 1969 Through Treaty Law, states are trying to achieve a

balance between:Certainty and FlexibilityObligation and Consent