領土紛爭과 國家實行의 拘束力ㆍ證據 地位 ― 一方宣言과 黙認 등 實質的 法源을 중심으로 ―

In international litigation on territorial disputes, it is not quite common for an international court or arbitral tribunal to adjudicate solely on the basis of such a formal source of international law as treaties or other international agreements. Rather, state practice such as unilateral declarations/statements, whether verbal or written, joint communiqué, admission or acquiescence plays as important a role as treaties or other agreements in many cases. An important precedent was established in 1928 when the Arbitrator Huber in the Island of Palmas arbitration went to great lengths to hold that practice, as well as doctrines, recognizes that the continuous and peaceful display of territorial sovereignty was as good as a title. In a similar vein, the Permanent Court of International Justice(PCIJ) conceded the binding effect of unilateral statements or undertakings in the 1933 Legal Status of Eastern Greenland case. The PCIJ's jurisprudence was subsequently followed and confirmed by the International Court of Justice(ICJ) in the 1974 Nuclear Tests cases when it pronounced that the legally binding effect of a unilateral undertaking, commitment or engagement is based on the principle of good faith or on confidence and trust, a fundamental principle of international law and also an essential element for the security of international intercourse. Likewise, admission or acquiescence per se may not, unlike effective occupation or cession, create a legal title to territory. But it is frequently relied upon and invoked by the ICJ as the basis of creating legal obligations(estoppel)[the 1951 Fisheries case, followed in the 1953 Minquiers and Ecrehos case, the 1962 Temple of Preah Vihear case, the 1969 North Sea Continental Shelf cases and the 1984 Gulf of Maine case] and also as the evidence recognizing or approving of territorial titles or rights. For these reasons, state practice as represented in unilateral declarations, admissions or acquiescence in territorial disputes should be taken seriously as a material source of international law binding upon the parties. Indeed, the dichotomy of formal and material sources of international law is misleading in that even a UN General Assembly resolution adopted on unanimity does not, as a matter of law and principle, legally bind its member countries.