The number of peremptory norms is considered limited but not exclusively catalogued.

There are often disagreements over whether a particular case violates a peremptory norm.

One positive right considered to be a peremptory norm is the right to use self-defense.

Assessing the legitimacy of laws that do not meet peremptory norms of international law.

Some peremptory norms define criminal offences considered to be enforceable against not only states but also individuals.

Refugee law encompasses both customary law, peremptory norms, and international legal instruments.

The UN cannot circumvent peremptory norms and its resolutions are subject to judicial review.

A treaty is null and void if it is in violation of a peremptory norm.

Rights that cannot be derogated for reasons of national security in any circumstances are known as peremptory norms or jus cogens.

The relatively new concept of peremptory norms seems to be at odds with the traditionally consensual nature of international law considered necessary to state sovereignty.

Some principles of customary law have achieved the force of peremptory norms, which cannot be violated or altered except by a norm of comparable strength.

During his stay in Nancy, Muszkat created new ideas about public international law, peremptory norm and international problems (especially to concern of Third World).

The only limit to pacta sunt servanda are the peremptory norms of general international law, called jus cogens (compelling law).

The treaty allows for the emergence of new peremptory norms, but does not specify any peremptory norms.

All jus cogens are customary international law through their adoption by states, but not all customary international laws rise to the level of peremptory norms.

Certain norms of international law achieve the binding force of peremptory norms (jus cogens) as to include all states with no permissible derogations.

Under Article 53 of the Vienna Convention on the Law of Treaties, any treaty that conflicts with a peremptory norm is void.

The universality principle (principle of universal jurisdiction) is closely aligned with the international law doctrine of peremptory norms (jus cogens).

But it was the judgments of the Permanent Court of International Justice that show the earliest application of peremptory norms as non derogable.

The earliest case was in its judgment of the matters between the United Kingdom v. Germany in 1923, stating that sovereignty cannot be an excuse to derogate peremptory norms.

Ius publicum was also used to describe obligatory legal regulations (today called ius cogens-this term is applied in modern international law to indicate peremptory norms that cannot be derogated from).

It is commonly accepted that, at least since World War II, genocide has been illegal under customary international law as a peremptory norm, as well as under conventional international law.

Neither the individual State responsibility of a State that concludes a treaty contrary to jus cogens, nor the rights of third States where a treaty violates a peremptory norm of international law are specified.

Whilst the prevailing legal advice is that the agreement is not, on the face of it, in contravention of international law, there is a clear risk of the breach of peremptory norms in its implementation.

It is debatable whether non-refoulement is a jus cogens (peremptory norm) of international law that forbids the expulsion of a refugee into an area, usually their home-country, where the person might be again subjected to persecution.