Sources of International Law

Since time immemorial, states and peoples have entered into formal relationships with each other. Over the ages, traditions have developed on how such relationships are conducted. These are the traditions that make up modern ‘international law’. Like domestic law, international law covers a wide range of subjects such as security, diplomatic relations, trade, culture and human rights, but it differs from domestic legal systems in a number of important ways. In international law there is no single

legislature, nor is there a single enforcing institution. Consequently, international law can only be established with the consent of states and is primarily dependent on self-enforcement by those same states. In cases of non-compliance there is no supra-national institution; enforcement can only take place by means of individual or collective actions of other states.

This consent, from which the rules of international law are derived, may be expressed in various ways. The obvious mode is an explicit treaty, imposing obligations on the states parties. Such ‘treaty law’ constitutes a dominant part of modern international law. Besides treaties, other documents and agreements serve as guidelines for the behaviour of states, although they may not be legally binding. Consent may also be inferred from established and consistent practice of states in conducting their relationships with each other. The sources of international law are many and states commit to them to different degrees. The internationally accepted classification of sources of international law is formulated in Article 38 of the Statute of the International Court of Justice. These are:

a) International conventions, whether general or particular;

b) International custom, as evidence of general practice accepted as law;

c) The general principles of law recognised by civilised nations;

d) Subsidiary means for the determination of rules of law such as judicial decisions and teachings of the most highly qualified publicists.

These sources will be analysed below.

A. International conventions

International treaties are contracts signed between states. They are legally binding and impose mutual obligations on the states that are party to any particular treaty (states parties). The main particularity of human rights treaties is that they impose obligations on states about the manner in which they treat all individuals within their jurisdiction. 

Even though the sources of international law are not hierarchical, treaties have some degree of primacy. More than forty major international conventions for the protection of human rights have been adopted. International human rights treaties bear various titles, including ‘covenant’, ‘convention’ and ‘protocol’; but what they share are the explicit indication of states parties to be bound by their terms. 

Human rights treaties have been adopted at the universal level (within the framework of the United Nations and its specialised agencies, for instance, the ILO and UNESCO) as well as under the auspices of regional organisations, such as the Council of Europe (CoE), the Organisation of American States (OAS) and the African Union (AU) (formerly the Organisation of African Unity (OAU)). These organisations have greatly contributed to the codification of a comprehensive and consistent body of human rights law. 



Human rights had already found expression in the Covenant of the League of Nations, which led, inter alia, to the creation of the International Labour Organisation. At the San Francisco Conference in 1945, held to draft the Charter of the United Nations, a proposal to adopt a ‘Declaration on the Essential Rights of Man’ was put forward but was not examined because it required more detailed consideration than was possible at the time. Nonetheless, the UN Charter clearly speaks of ‘promoting and encouraging respect for human rights and for fundamental freedoms for all without distinction as to race, sex, language or religion’ (Article 1, para. 3). The idea of promulgating an ‘international bill of rights’ was developed immediately afterwards and led to the adoption in 1948 of the Universal Declaration of Human Rights (UDHR).

The UDHR, adopted by a resolution of the United Nations General Assembly (UNGA), although not a treaty, is the earliest comprehensive human rights instrument adopted by the international community. On the same day that it adopted the Universal Declaration, the UNGA requested the UN Commission on Human Rights toprepare, as a matter of priority, a legally binding human rights convention. Wide differences in economic and social philosophies hampered efforts to achieve agreement on a single instrument, but in 1954 two draft conventions were completed and submitted to the UNGA for consideration. Twelve years later, in 1966, the International Covenant  on Economic, Social and Cultural Rights (ICESCR) and the International Covenant on Civil and Political Rights (ICCPR) were adopted, as well as the First Optional Protocol to the ICCPR, which established an individual complaints procedure. Both Covenants and the Optional Protocol entered into force in 1976. A Second Optional Protocol to the ICCPR, on the abolition of the death penalty, was adopted in 1989 and entered into force in 1991. 

The ‘International Bill of Human Rights’ consists of the Universal Declaration of Human Rights, the ICESCR and the ICCPR and its two Optional Protocols. The International Bill of Rights is the basis for numerous conventions and national constitutions. 

The ICESCR and the ICCPR are key international human rights instruments. They have a common Preamble and Article 1, in which the right to self-determination is defined. The ICCPR primarily contains civil and political rights. The supervisory body is the Human Rights Committee. The Committee provides supervision in the form of review of reports of states parties to the Covenant, as well as decisions on inter-state complaints. Individuals alleging violations of their rights under the Covenant can also bring claims against states to the Committee provided the state concerned is party to the First Optional Protocol. By March 2010, a total of 165 states were parties to the Covenant, 113 to the First Optional Protocol and 72 to the Second Optional Protocol (see II§1.C).

The ICESCR consists of a catalogue of economic, social and cultural rights in the same vein as the ‘social’ part of the UDHR. Supervision is provided for in the form of reporting by states parties to the Covenant and review of state reports has been entrusted by the UN Economic and Social Council (ECOSOC) to the Committee on Economic, Social and Cultural Rights. An Optional Protocol establishing a system of individual and collective complaints was adopted on 10 December 2008. It will be opened for signature and ratification in March 2009.In March 2010, a total of 160 states were parties to the Covenant (see II§1.C).

Besides the International Bill of Human Rights, a number of other instruments have been adopted under the auspices of the UN and other international agencies. They may be divided into three groups: 

a) Conventions elaborating on certain rights, inter alia:

  •  The Convention on the Prevention and Punishment of the Crime of Genocide (1948)
  •  ILO 98 concerning the Right to Organise and to Bargain Collectively (1949)
  •  The Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment (1984)
  •  International Convention for the Protection of All Persons from Enforced Disappearance (2006) 

b) Conventions dealing with certain categories of persons which may need special    protection, inter alia:

  •  The Convention relating to the Status of Refugees (1951), and the 1967 Protocol thereto
  •  The Convention on the Rights of the Child (1989)
  •  Optional Protocol to the Convention on the Rights of the Child on the involvement of children in armed conflicts (2000)
  •  Optional Protocol to the Convention on the Rights of the Child on the sale of children,child prostitution and child pornography (2000)
  •  ILO 169 concerning Indigenous and Tribal Peoples in Independent Countries (1989)
  •  The International Convention on the Protection of the Rights of All Migrant Workers andMembers of Their Families (1990)
  •  The Convention on the Rights of Persons with Disabilities (2006) 

c) Conventions seeking to eliminate discrimination

  •  ILO 111 concerning Discrimination in respect of Employment and Occupation (1958)
  •  UNESCO Convention against Discrimination in Education (1960)
  •  The International Convention on the Elimination of All Forms of Racial Discrimination (1965)
  •  The International Convention on the Suppression and Punishment of the Crime of Apartheid(1973)
  •  The Convention on the Elimination of All Forms of Discrimination Against Women (1979)and its Optional Protocol (2000) 



The UN Charter encourages the adoption of regional instruments for the establishment of human rights obligations, many of which have been of crucial importance for the development of international human rights law. The Council of Europe adopted the European Convention for the Protection of Human Rights and Fundamental Freedoms in 1950 (see II§2.C), supplemented by the European Social Charter in 1961(see II§2.C), the European Convention for the Prevention of Torture and Inhuman or DegradingTreatment or Punishment in 1987 (see II§2.C), and the Framework Convention on National Minorities in 1994 (see II§2.C).

The American Convention on Human Rights was adopted in 1969, under the auspices of the Organisation of American States (see II§3.B). This Convention has been complemented by two protocols, the 1988 Protocol of San Salvador on economic, social and cultural rights and the 1990 Protocol to abolish the death penalty. Other Inter-American Conventions include the Convention to Prevent and Punish Torture (1985), the Convention on the Forced Disappearances of Persons (1994), the Convention on the Prevention, Punishment and Eradication of Violence against Women (1995) and the Inter-American Convention on the Elimination of All Forms of Discrimination against Persons with Disabilities (see II§3.B). 

In 1981, the Organisation of African Unity, now the African Union, adopted the African Charter on Human and Peoples’ Rights (see II§4.B). Three protocols to the Charter have been adopted: the Additional Protocol on the Establishment of the African Court on Human and Peoples’ Rights (1998), the Protocol on the Rights of Women in Africa (2003) and the Protocol on the Statute of the African Court of Justice and Human Rights (2008) (see II§4.B). Other African instruments include the Convention Governing the Specific Aspects of Refugee Problems in Africa (1969) (see II§4.B) and the African Charter on the Rights and Welfare of the Child (1990) (see II§4.B).


B. International custom 

Customary international law plays a crucial role in international human rights law. The Statute of the International Court of Justice refers to ‘general practice accepted as law’. In order to become international customary law, the ‘general practice’ needs to represent a broad consensus in terms of content and applicability, deriving from a sense that the practice is obligatory (opinio juris et necessitatis). Customary law is binding on all states (except those that may have objected to it during its formation), whether or not they have ratified any relevant treaty.  

One of the important features of customary international law is that customary law may, under certain circumstances, lead to universal jurisdiction or application, so that any national court may hear extra-territorial claims brought under international law. In addition, there also exists a class of customary international law, jus cogens, or peremptory norms of general international law, which are norms accepted and recognised by the international community of states as a whole as norms from which noderogation is permitted. Under the Vienna Convention on the Law of Treaties (VCLT) any treaty which conflicts with a peremptory norm is void. 

Many scholars argue that some standards laid down in the Universal Declaration of Human Rights (which in formal terms is only a resolution of the UNGA and as such not legally binding) have become part of customary international law as a result of subsequent practice; therefore, they would be binding upon all states. Within the realm of human rights law the distinction between concepts of customary law, treaty law and general principles of law are often unclear. 

The Human Rights Committee in its General Comment 24 (1994) has summed up the rights which can be assumed to belong to this part of international law which is binding on all states, irrespective of whether they have ratified relevant conventions, and to which no reservations are allowed: 

[A] State may not reserve the right to engage in slavery, to torture, to subject persons to cruel,    inhuman or degrading treatment or punishment, to arbitrarily deprive persons of their lives, to     arbitrarily arrest and detain persons, to deny freedom of thought, conscience and religion, to       presume a person guilty unless he proves his innocence, to execute pregnant women and    children,          to permit the advocacy of national, racial or religious hatred, to deny to persons of   marriageable age the right to marry, or to deny to minorities the right to enjoy their own       culture, profess their own religion, or use their own language. And [...] the right to a fair trial [...]. 

Although this list is subject to debate and could possibly be extended with other rights not in the field of civil and political rights (for instance, genocide and large parts of the Four Geneva Conventions on International Humanitarian Law), the Committee underlines that there is a set of human rights which de jure are beyond the (politically oriented) debate on the universality of human rights. 


C. General principles of law 

In the application of both national and international law, general or guiding principles are used. In international law they have been defined as ‘logical propositions resulting from judicial reasoning on the basis of existing pieces of international law’.

At the international level, general principles of law occupy an important place in case-law regarding human rights. A clear example is the principle of proportionality, which is important for human rights supervisory mechanisms in assessing whether interference with a human right may be justified. Why are general principles used? No legislation is able to provide answers to every question and to every possible situation that arises. Therefore, rules of law or principles that enable decision-makers and members of the executive and judicial branches to decide on the issues before them are needed. General principles of law play two important roles: on the one hand, they provide guidelines for judges, in particular, in deciding in individual cases; on the other hand, they limit the discretionary power of judges and of members of the executive in their decisions in individual cases.


D. Subsidiary means for the determination of rules of law 

According to Article 38 of the Statute of the International Court of Justice, judicial decisions and the teachings of the most qualified publicists are ‘subsidiary means for the determination of rules of law’. Therefore, they are not, strictly speaking, formal sources, but they are regarded as evidence of the state of the law. 

As for the judicial decisions, Article 38 of the Statute of the International Court of Justice is not confined to international decisions (such as the judgements of the International Court of Justice, the Inter-American Court, the European Court and the future African Court on Justice and Human Rights); decisions of national tribunals relating to human rights are also subsidiary sources of law. 

The writings of scholars contribute to the development and analysis of human rights law. Compared to the formal standard setting of international organs the impact is indirect. Nevertheless, influential contributions have been made by scholars and experts working in human rights fora, for instance, in the UN Sub-Commission on the Promotion and Protection of Human Rights, as well as by highly regarded NGOs, such as Amnesty International and the International Commission of Jurists.


E. Other contributions to standard setting 

Some instruments or decisions of political organs of international organisations and human rights supervisory bodies, although they are not binding on states parties per se, nonetheless carry considerable legal weight. 

Numerous international organs make decisions that concern human rights and thereby strengthen the body of international human rights standards. Such nonbinding human rights instruments are called ‘soft law’, and may shape the practice of states, as well as establish and reflect agreement of states and experts on the interpretation of certain standards. 

Every year, the UNGA and the Human Rights Council adopt dozens of resolutions and decisions dealing with human rights. Organisations such as the ILO and the various political organs of the Council of Europe also adopt such resolutions. Some of these resolutions, sometimes called declarations, adopt specific standards on specific human rights that complement existing treaty standards. Prominent examples include the Declaration on the Human Rights of Individuals Who Are Not Nationals of the

Country in Which They Live, adopted by the UNGA in 1985 (Resolution 40/144, 13 December 1985), the Guiding Principles on Internal Displacement, adopted by the UN Commission on Human Rights in 1999 (Doc E/CN.4/1998/53/Add.2) and the United Nations Declaration on the Rights of Indigenous Peoples, adopted by the UNGA in 2007 (Resolution 61/295, 13 September 2007). Numerous declarations adopted by the UNGA have later given rise to negotiations leading to treaty standards. Not all resolutions and decisions aim at standard setting; many deal with concrete situations where diverging political interests come more into play. 

                                   1. DECISIONS OF POLITICAL ORGANS

Decisions of political organs involving political obligations play a special role and can have an impact on human rights standard setting, e.g., certain documents of the Organisation on Security and Co-operation in Europe (OSCE) (Conference on Security and Co-operation in Europe until 1995). Since 1975, the OSCE has devoted much attention to the so-called Human Dimension of European cooperation. OSCE documents are often drafted in a relatively short period of time and do not pretend to be legally binding. Thus, they offer the advantage of flexibility and relevance to current events exercising influence upon states. For instance, the Document of the Copenhagen Meeting of the Conference of the Human Dimension of the CSCE of 1990 made optimal use of the changes that had taken place in Europe after the fall of the Berlin Wall in 1989. This document included paragraphs on national minorities, which have been used as standards to protect minorities and as guidelines for later bilateral treaties. Although this kind of document reflects the dynamism of international human rights law, some experts worry that the political nature of these documents may lead to confusion, as newer texts might contradict existing instruments or broaden the scope of attention for human rights excessively by including too many related issues.


                                   2. DECISIONS OF SUPERVISORY ORGANS

Numerous human rights supervisory mechanisms have been established to monitor the compliance by states with international human rights standards. Within the UN context, these supervisory bodies are often called ‘treaty bodies’. They interpret international treaties, make recommendations and, in some cases, make decisions on cases brought before them. These decisions, opinions and recommendations may not be legally bindingper se, but their impact on international human rights law (standards) is significant. 

In this context, treaty bodies often prepare so-called General Comments or Recommendations, elaborating on the various articles and provisions of their respective human rights instruments. The purpose of these general comments or recommendations is to assist the states parties in fulfilling their obligations. The Human Rights Committee and the Committee on Economic, Social and Cultural Rights are highly regarded for their practice in this respect. These general comments/recommendations reflect the developments within each Committee as to the interpretation of specific provisions and they aim to provide authoritative guidance to states parties. As such, they have a significant influence on the behaviour of states parties.


F. Concluding remarks

Most states are bound by numerous international instruments guaranteeing a broad range of human rights. What happens when a state is bound by two international instruments setting out diverging levels of protection of a particular human right? The general rule is that when a state is bound by numerous instruments, it is to implement the most far-reaching obligation or highest standard. Most human rights conventions contain special provisions to this effect. For instance, Article 5(2) ICCPR and Article 5(2) ICESCR state that ‘There shall be no restriction upon or derogation from any of the fundamental human rights recognised or existing in any state party to the present Covenant pursuant to law, conventions, regulations or custom on the pretext that the present Covenant does not recognise such rights or that it recognises them to a lesser extent.’ 

In the same vein, Article 55 ECHR sets out that ‘Nothing in this Convention shall be construed as limiting or derogating from any of the human rights and fundamental freedoms which may be ensured under the laws of any High Contracting Party or under any other agreement to which it is a Party.’ Similarly, Article 41 CRC provides that nothing in the Convention shall affect any provisions which are more conducive to the realisation of the rights of the child –either in the law of a state party or in international law in force in that state. 

Within the realm of standard setting, the number of ratifications and accessions to conventions merits special attention. Widely ratified human rights conventions have greater value and impact, and reinforce the universal character of human rights law, as well as the equality of all human beings under that law. Wide accession or ratification (with the least possible number of reservations) contributes greatly to ensuring equal application of human rights standards. 

Many scholars contend that much of the standard-setting work has been completed. In addition, it has been argued that in recent decades there has been an excessive proliferation of standards, and what is needed is a means for better implementation of the existing norms. However, although the basic human rights have been roughly defined, it may, for instance, emanate from consistent decisions of supervisory mechanisms that further elaboration is needed. Better legal protection may be necessary for, inter alia, human rights defenders, lesbian, gay, bisexual and transgender people and persons belonging to indigenous peoples, or in relation to particular issues such as transitional justice or scientific advances in biomedicine. 



      UN treaty monitoring bodies have begun the practice of preparing General Comments or Recommendations on the provisions of their respective treaties. 

     As indicated by the Committee on Economic, Social and Cultural Rights ‘the Committee endeavours, through its general comments, to make the experience gained so far through the examination of States’ reports available for the benefit of all States Parties in order to assist and promote their further implementation of the Covenant; to draw the attention of the States Parties to insufficiencies disclosed by a large number of reports; to suggest improvements in the reporting procedures; and to stimulate the activities of the States Parties, international organisations and the specialised agencies concerned in achieving progressively and effectively the full realisation of the rights recognised in the Covenant.’ 

      The General Comments or Recommendations are useful tools to clarify the normative content of the Covenants because they are general in nature and provide an abstract picture of the scope of the obligations. General Comments and Recommendations enable the Committees to announce their interpretations of the different provisions of the treaties, and the interpretations of the normative scope of the treaties set out in the General Comments/ Recommendations have achieved a significant degree of acceptance by states parties. 

      As of March 2010, the Committee on Economic, Social and Cultural Rights had adopted 21 General Comments; the Human Rights Committee had adopted 33 General Comments; the Committee on the Elimination of Racial Discrimination had adopted 33 General Recommendations; the Committee on the Elimination of Discrimination against Women had adopted 26 General Recommendations; the Committee against Torture had adopted two General Comments; and the Committee on the Rights of the Child had adopted 12 General Comments. The Committees established under the CRPD and CMW have yet to adopt General Comments.

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