Difficulties in demonstrating the subjective element have been recognised by subsequent courts and, in practice, the emphasis has moved to objective evidence of consistent State practice. The International Court adopted a more useful modern approach to custom in the Nicaragua case ([1986] ICJ 14): “The court does not consider that, for a rule to be established as customary, the corresponding practice must be in absolutely rigorous conformity with the rule. In order to deduce the existence of customary rules, the court deems it sufficient that the conduct of States should, in general, be consistent with such rules, and that instances of State conduct inconsistent with a given rule should generally have been treated as breaches of that rule, not as indications of the recognition of a new rule.” While it remains necessary to satisfy the twin elements of State practice and opinio juris when assessing the status of a purported customary rule, the courts today are more concerned to document State activities as the best evidence of their express or implied consent to a new obligation. What are ‘soft’ and ‘hard’ international law? An important issue of customary law arises where an emerging rule does not yet satisfy the requirements for the creation of custom but is regarded as likely to do so over time. Such an emerging rule is described as lex ferenda. Recognition of evolving law is considered by legal commentators as “soft law”, or as an evolving norm that needs to be taken into account when assessing the existence of a binding rule. Not only are there significant difficulties as a matter of methodology in determining whether a customary rule exists, but also it is necessary to take into account the dynamic nature of international law and the place of emerging principles. The significance of evolving norms creates a particular difficulty when advising on international human rights. Most States are party to the fundamental international human rights documents and treaties such as the Universal Declaration on Human Rights, International Covenant on Civil and Political Rights and the Conventions on Genocide, Torture, Sex Discrimination and Racial Discrimination. However, the more complex provisions of multilateral human rights agreements over the last 20 years have not yet attracted general adherence. For this reason, and while treaties will apply as between the States parties, the principles they contain do not yet have the status of customary law. Such treaty based evolving norms will not be binding on non-parties. Equally however, these principles may well be evolving or crystallising into accepted principles of customary law. 33