ABSTRACT
This chapter provides examples to illustrate the vastness of possible sources for the determination of state practice. In the absence of a taxative list of the physical manifestations of states, jurisprudence and doctrine have determined a number of characteristics that are relevant in assessing state practice: scope, quality, and time. Some have argued that general principles of law may be viewed as customary international law without the element of state practice. The practice of or within international organizations may play an even greater role in the debate on the subjective element of customary international law, opinio iuris. The International Court of Justice has failed to embark on any serious analysis of state practice and opinio iuris, while at the same time confirming its validity. The International Court of Justice itself has included "administrative acts or attitudes", "legislation", "acts of the judiciary" and "treaties".
