States and the criteria for Statehood.

Independent States remain the primary subject of IL as they occupy the central position in the international community. However, it is necessary to analyse what is a State? In accordance with the article 1 (1) of the 1933 Montevideo Convention on Rights and Duties of States:

The State as a person of International Law should possess the following qualifications:

(a) a permanent population;

(b) a defined territory;

(c) government; and

(d) capacity to enter into relations with other States.

These joint criteria or requirements are necessary to form a State, which possesses sovereignty and even so, international personality.

There is a requirement that is not included in the abovementioned provision that is the recognition. Some scholars consider that recognition is not required for constituting a State in basis of the principle of effectivity. Indeed, State practice shows that statehood need not necessarily be equated with effectiveness, and thus that conditions unrelated to effectiveness are relevant to the determination of whether an entity should be regarded as a State under international Law. Other scholars believe that recognition is required.

Subjects of International Law

Subjects of International Law. 


A subject of International Law is defined as an entity capable of possessing international rights and duties and having capacity to protect its rights by bringing international claims.

Critique: it is not an univocal concept and provokes a vicious circle. Why?

  • Because what is a subject of IL? Somewhat which has capacity to protect its rights by bringing international claims. Which entity can make that? A subject of IL.

History and development of its concept.

  • During the 18th and 19th century, subjects of IL were identified as States. However, some atypical entities were recognised as subjects of IL (e.g. free cities, Federations, etc).
  • During the 19th century, IGOs arose in order to ensure efficient cooperation in areas of common interest. Due to its legislative and enforcement powers were considered as subjects of IL.
  • After WWI, it became obvious that entities other than States, which had no physical control over any territory were important players in the international arena. However, during the period between WWI and WWII, the matter of whether the League of Nations had international personality was never conclusively decided.

After WWII with the creation of the UN and the proliferation of international organisations the traditional views on subjects of IL changed. The ICJ in Reparation for Injuries Suffered in the Service of the United Nations (Advisory Opinion) (1949) held that the UN possesses legal personality but limited as the conferred competences granted by their constitutional treaties. As consequence, the UN has legal capacity to bring a claim for reparations concerning injuries which one of its employees had suffered while in active service of the organisation.

  • Currently, subjects of International Law are:
    • Entities which can potentially become States & entities with State-like.
    • Some de facto regimes.
    • Insurgents and belligerents.
    • National liberation movements which represent peoples who are entitled to exercise their right to self-determination.
    • IGOs & UN missions created by the UNSC resolutions to administer certain territories during the transition period leading to self-governance of those territories. Such missions enjoy full legal personality during the transition period.
    • NGOs, MNCs and indigenous people. It can be argued that NGOs, MNCs are subjects of IL in accordance with LaGrandGermany v. USA (Judgment)
    • Individuals. Historically, individuals were excluded from the concept of subjects of IL. However, some scholars argued that currently the globalisation, privatisation, feminism and the fragmentation of International Law have radically changed its concept. Other scholars trying to reconcile the doctrine of subjects of IL with the appearance of new entities: subjects of IL and object of IL. Higgins proposes to distinguish two concepts: subjects of IL and participants.

General principles of International Law

1. Origin. From the Latin noun “Principia”: first, foremost, leading, chief, more neccesary. 

2. Definition.  Principles are the pinnacle of the legal system and are intended to serve as basic guidelines for the life of the whole community. Main values inferred from municipal laws or from the nature of international community.

3. Aims.

  • i) general obligations;
  • ii) set out the policy lines and the basic goals of State agencies;
  • iii) interpretation.

Regulation (general principles of International Law)

Regulation: Article 2 the UN Charter.

  1. Sovereign equality of Member States of the UN.
  2. The ban on the threat of use of force.
  3. Peaceful settlement of disputes, which are extended to all members of the international community.

UN 1970 Declaration on Friendly relations (resolution 2625- XXV)

Considering that the progressive development and codification of the following principles:

1.The principle that States shall refrain in their international relations from the threat or use of force against the territorial integrity or political independence of any State, or in any other manner inconsistent with the purposes of the United Nations,

2.The principle that States shall settle their international disputes by peaceful means in such a manner that international peace and security and justice are not endangered,

3.The duty not to intervene in matters within the domestic jurisdiction of any State, in accordance with the Charter,

4.The duty of States to co-operate with one another in accordance with the Charter,

5.The principle of equal rights and self-determination of peoples,

6.The principle of sovereign equality of States,

7.The principle that States shall fulfil in good faith the obligations assumed by them in accordance with the Charter, so as to secure their more effective application within the international community, would promote the realization of the purposes of the United Nations,

This list is considered as numerus clausus, that is, a closed list. 

Jus cogens

  • Jus cogens rules have the highest status in the informal hierarchy of souces of IL.
  • Difference between jus cogens and erga omnes rules.– The main difference btw a rule of jus cogens and a rule that creates an obligation erga omnes is that all jus cogens rules create erga omnes obligations, but only some rules creating erga omnes obligations are rules of jus cogens.
  • Requirements: it must be accepted and recognised by the international community of States as a whole as a rule from which no derogation is permitted; and which can be modified only by a subsequent norm of general international law having the same character.
  • Effects: States cannot deviate from jus cogens rule. A new State must accept it and it cannot be changed without the approval of the international community as a whole.
  • Regulation: article 53 VCLT. Definition (art. 53 VCLT): ‘a norm accepted and recognised by the international community of states as a whole as a norm from which no derogation is permitted and which can be modified only by a subsequent norm of general international law having the same character’.
  • Article 53 VCLT provides that a treaty is void if, at the time of its conclusion, it conflicts with a peremptory rule of international law. As to an existing treaty, under Article 64 VCLT if a new rule of jus cogens emerges and a treaty conflicts with it, the treaty becomes void and terminates. However, specific procedures set out in Articles 65 and 66 VCLT must be followed if a party to a treaty claims that the existing treaty breaches a new established in accordance with the procedures contained in article 65 and 66 VCLT. Consequently, a party to a traty must follow these procedures in order to invalidate it while a State, or an IGO, which is not a party to a treaty, is not required to follow them and therefore may claim that a particular treaty is invalid on the ground that it clashes with a jus cogens rule. An example of a situation where a treaty was invalidated on the ground of a violation of jus cogenes providedad by the IACtHR in Aloeboetoe Case.
  • The VCLT does not freeze the rules of jus cogens. To the contrary, its article 64 highlights the evolutionary nature of jus cogens. It states that ‘if a new peremptory norm of general law emerges any existing treaty which is in conflict with that norm becomes void and terminates’. However, in practice it is difficult to envisage a situation where a new rule of jus cogens would overturn an existing rule bearing in mind that by their nature jus cogens rules are not only accepted but also recognised by the international community of States as a whole.
  • The international community has not agreed on any list of peremptory rules. However, in the case Concerning Questions relating to the obligation to extradite or prosecute (Belgium v. Senegal) the ICJ suggested that in order to identify a rule of jus cogens, procedures similar to those relating to the identification of any rule of customary law should be carried out.

Assesment of jus cogens

In the light of more recent judgements of the ICJ the role of jus cogens seems to be undermined rather than enhanced.

  • The prohibition of torture: In the Case Concerning Questions Relating to the Obligation to Extradite or Prosecute (Belgium v. Senegal.
  • Rules relating to State immunity are rules of procedure, jus cogens are rules of substance. Conflict btw them conceptually impossible.
  • Erga omnes obligations. In the Barcelona Traction, Light and Power: the ICJ making reference to these erga omnes obligations stated that: ‘Such obligations derive, for example, in contemporary International Law, from the outlawing of acts of aggression, and of genocide, and also from the principles and rules concerning the basic rights of the human peron, including protection from slavery and racial discrimination.
  • The 2005 Resolution of the Institute of International Law examines erga omnes obligations: the prohibition of acts of aggression, the prohibition of genocide, obligations concerning the protection of basic human rights, obligations relating to the environment of common space

Termination of a treaty

In the following situations a treaty may be terminated:

  • Termination of a treaty in accordance with the terms of the treaty: (art.54 (a)’ In conformity with the provisions of the treaty’)
  1. The treaty may be for a specified period and terminate at the end of that period.
  2. The treaty may be for a minimum period with a right to withdraw at the expiry of that period.
  3. The treaty may be for a specific purpose and terminate on completion of that purpose.
  4. The treaty may allow withdrawal at any time.
  5. The treaty may allow withdrawal in special circumstances.
  • Termination by agreements. If the treaty does not recognise this circumstances, it is possible if ‘it is established that the parties intended to admit the possibility of denuntiation or withdrawal or, b) a right of denunciation or withdrawal may be implied by the nature of the treaty. Period of time> minim period of 12 months.
  • Implied termination where parties enter into another treaty on the same subject (article 59).
  • Termination of a treaty which is in conflict with a jus cogens rule (art. 64 VCLT).

Amendment vs. Modification of treaties


The term «amendment» refers to the formal alteration of treaty provisions affecting all the parties to the particular agreement. Such alterations must be effected with the same formalities that attended the original formation of the treaty. Many multilateral treaties lay down specific requirements to be satisfied for amendments to be adopted. In the absence of such provisions, amendments require the consent of all the parties.

Article 39 VCLT: ‘A treaty may be amended by agreement between the parties’.

1st: The particular procedure of the concerning treaty.

2nd: if the concerning treaty has not provided any rule, article 40 VCLT establishes:

  • Amendments must be notified to the rest of the States. Any State could negotiate and conclude that amendment.
  • ‘The amending agreement does not bind any State already a party to the treaty which does not become a party to the amending agreement’.

Modification: a number of parties agree to modify the effects of the treaty among themselves. The term «modification» refers to the variation of certain treaty provisions only as between particular parties of a treaty, while in their relation to the other parties the original treaty provisions remain applicable. If the treaty is silent on modifications, they are allowed only if the modifications do not affect the rights or obligations of the other parties to the treaty and do not contravene the object and the purpose of the treaty.

In accordance with article 41 VCLT, only when it is allowed expressely, it is not prohibited expressely, it does not affect ‘the enjoyment by the other parties of their rights under the treaty or the performance of their obligations’ or it is not incompatible ‘with the effective execution of the object and purpose of the treaty as a whole’.


A reservation must be communicated to the contracting States or IGOs and other States or IGOs entitled to become parties to the relevant treaty in order to ensure that they can formulate an objection to it within a period of 12 months after being notified of it.

General rule of a treaty: reservations are allowed exceted in package-deal treaties. Two are the classes of revervations to treaties (see article 19 &20 VCLT):

  • Permissible reservations: expressely permitted by the relevant treaty and those which are compatible with the object and purpose of that reaty. Reservations operate on the basis of reciprocity and, if they are permissible, create the following relationships between the reserving State and the other contracting States.
  • Non-permissible reservations: the ones prohibited expressely or implictly by the concerning treaty, and reservations which are incompatible with the object and purpose of the relevant treaty.

Objection. Any signatory or contracting state has the option of objecting to a reservation, inter alia, if, in its opinion, the reservation is incompatible with the object and purpose of the treaty. The objecting state may further declare that its objection has the effect of precluding the entry into force of the treaty as between objecting and reserving states. [Art.20-23, Vienna Convention on the Law of Treaties 1969]

Main principles of the 1969 VCLT

  • The principle of free consent means that a State cannot be bound by a treaty to which it has not consented (article 34 VCLT).
  • Pacta sunt servanda (agreements must be kept) is embodied in article 26 VCLT: ‘Every treaty in force is binding upon the parties to it and must be performed by them in good faith‘. Likewise, the concerning treaty does not affect on a third party.- The maxim pacta tertiis nec nocent nec prosunt: article 34 VCLT. Exceptions:
    • International customary law.
    • If the treaty confers a right to a third party and consent its application.
  • The principle of good faith (applicable during all the life of a treaty, from its negotiation, through its performance and up to its termination).

Treaties interpretation

If there is a conflict between treaties, it is necessary to apply the interpretation clauses, that are articles 31 and 32  VCLT.

  • Textual interpretation
  • Systematic interpretation.
  • Teleological interpretation
  • Historical interpretation
  • The principle of effectiveness.

‘If treaties are contrary to jus cogens, jus cogens prevails. If treaties are contrary to the UN Charter, this legal instrument prevails under article 103 of the UN Charter».