To prove customary international law, one must demonstrate both sustained state practice and opino juris (the state's belief that it is complying with the norms of law). Each part must be examined individually. Due to the nature of human rights and their role in international law in the past, they have often been misunderstood and discredited. However, at the end of World War II, states began to debate the importance of this practice in order to safeguard certain universal principles regarding the fundamental rights of individuals. In 1948, the United Nations General Assembly adopted the Universal Declaration of Human Rights (UDHR) and although it is believed that there has not been sufficient state practice to simply affirm that this declaration is customary international law, it would be unrealistic to try to show that certain articles of the Universal Declaration of Human Rights (UDHR) are not. Steiner and Alston (2000; cited in Rothwell et al., 452) argue that the United Nations Charter "is legally binding, either as a matter of customary international law or as an authoritative interpretation of the United Nations Charter United ».