a formula that expresses one of the fundamental principles of international law: the duty of every state to conscientiously and completely fulfill its international obligations. In modern times the principle has been incorporated in the UN Charter and numerous international documents. For example, the Preamble and Article 2 (no. 2) of the UN Charter emphasize the duty of states to respect and carry out obligations arising from agreements and other sources of international law. The principle of faithfulness to international obligations was legally established in the Vienna Convention of the Law of Treaties (1969), which proclaimed that “every existing agreement is compulsory for its participants and must be conscientiously carried out by them.” Failure to observe the principle of pacta sunt servanda is considered a delict. The normative significance of the principle was elaborated in the Declaration of Principles of International Law, adopted at the 25th session of the UN General Assembly in 1970.