International Human Rights and the International Human Rights System A Manual for National Human Rights Institutions
Chapter 3:
What is international human rights law?
KEY QUESTIONS
• What is international law?
• What is the Universal Declaration of Human Rights?
• What is treaty law?
• What is international customary law?
1. WHAT IS INTERNATIONAL LAW?
International law is a body of law that governs the conduct of States and their relations with each other.
It has been developed over a number of centuries but its development over the last 100 years has
been broader and more comprehensive than at any early time, reflecting the rapidly increasing pace of
globalization.
There are two sources of international law:
• agreements between States, known by the general name of treaties
• custom.
Treaties are negotiated by States and set out legal obligations of States to each other. They bind
only those States that become parties to the treaties, through processes known as “accession” and
“ratification”.
• Accession is a single step process by which a State accepts the obligations of a treaty and
becomes a State party to it.
• Ratification is the second in a two-step process. The first step is signature, by which a State
indicates an intention to become a party to a treaty at some point in the future and makes a
commitment not to act in the meantime in a way that undermines the implementation of the
treaty. Upon ratification, the second step, the State accepts all of the obligations of the treaty and
is fully bound by its provisions.
Upon accession or ratification a State becomes a party to a treaty. A treaty only binds States parties
to it and a State party only has obligations towards other State parties, not towards States that are not
parties to the treaty.
International customary law, by contrast, binds all States and so is universal in its application. However,
the rules of international customary law are difficult to identify and define because they are found
not in written texts, like treaties, but in State practice. As a result they are often contested, obscure
and ill-defined. However, the International Court of Justice and other international tribunals are now
providing extensive guidance on the content of customary international law through a growing body of
jurisprudence. Much customary international law has also been codified in new treaties, such as the
Statute of the International Criminal Court.
Chapter 3: What is international human rights law? | 9