Customary International Law Flashcards
Customary international law
Results from a general and consistent practice of states that they follow from a sense of legal obligation
Two elements of customary international law
- State practice
- Opinio juris sive necessitatis
North Sea Cases 1969 on custom
“Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a rule of belief that this practice is rendered obligatory by the existence of a rule of law requiring it”
Where are the sources of IL listed?
Art 38(1) ICJ Statute
What is the problem with opinio juris?
That if you want to change the rule is to breach it and see if other states agree with what you’ve done
North Sea Cases 1969 on basic principles of transforming evidence into custom
“The states concerned must feel that they are conforming to what amounts to a legal obligation. The frequency or even habitual character of the acts is not in itself enough. There are many international acts… which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty.”
Kosovo Advisory Opinion, 2010 on custom
Declarations of independence not prohibited by international law, as proven by State practice in 18th, 19th and 20th centuries
Jurisdictional Immunities of the State, 2010 on custom
State practice is to be found in the judgments of national courts faced with the question whether a foreign State is immune, the legislation of those States which have enacted statutes dealing with immunity, the claims to immunity advanced by States before foreign courts and the statements made by States
Al Saadoon v SoS for Defence 2015
I: Whether there was an obligation to investigate allegations of that a person transferred into the custody of Iraq by UK forces was being detained in violation of Art 5?
H: No general state practice accepted as law that all credible allegations of inhuman or degrading treatment by state officials must be investigated
Serdar Mohammad v SoS for Defence 2015
I: Whether there was a rule of CIL permitting indefinite detention by an outside power involved in a third country in a non-international armed conflict?
H: Not enough state practice, also mentioned that the requirements of practice may not be as high when it comes to the emergence of a principle or a rule reflecting the laws of humanity, i.e. international humanitarian law
What is the unique thing about customary IL?
Once it’s taken to have developed, it binds all States irrespectively of whether or not the practice of a particular State has contributed to the development of that customary law
Anglo-Norwegian Fisheries Case 1951
I: Whether Norway’s method of drawing the baseline from which it measured its territorial sea was legally acceptable?
H: The persistent objector rule laid down, Norway always opposed the ten-mile rule so exempt
Positive obligations require greater consistency in state practice than passive obligations
The persistent objector rule
“In principle a state that indicates its dissent from a practice while the law is still in the process of development is not bound by that rule even after it matures”
Why is local custom problematic?
Because it accepts that international law can be different in different regions of the world
Asylum Case 1950
I: Can the Colombian government offer asylum under local custom?
H: No such local custom exists sufficient to be binding at international law. The Court held that the party which relies on a custom of this kind has the burden of establishing that the custom exists in such a way that it has become binding on the other party, through constant and uniform usage of the states
Rights of Navigation 2009
There was a local custom between Costa Rica and Nicaragua
“For the Court, the failure of Nicaragua to deny the existence of a right arising from the practice which had continued undisturbed and unquestioned over a very long period, is particularly significant”
General principles of law
A reservoir of principles which an international judge is authorised by Art 38 to apply in an international dispute, if their application appears relevant and appropriate in the different context of international relations
Art 59 ICJ Statute
Non-binding and non-precedential character of the decisions of the ICJ
Nuclear Weapons Advisory Opinion 1996
GA resolutions, even though not binding, may sometimes have normative value - in certain circumstances, they can provide evidence for establishing the existence of a rule or the emergence of an opinio juris
Art 25 UN Charter
UN Members have to accept and carry out decisions of the Security Council
North Sea Continental Shelf on custom and treaties
The treaty provision, in order to give rise to the custom, must be capable of general application and must be intended to be the basis for future state practice, as well as being supported by opinio juris and acts of state practice by non-parties to the treaty
Gulf of Maine on customary international law
It is ideally suited to the development of general principles and it’s always available to fill the void if treaty fails
