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World Court Digest



II. Substantive International Law - Second Partv
1. TERRITORY OF STATES
1.2. Boundaries
1.2.1.Land Boundaries

¤ Case Concerning Sovereignty over
Pulau Ligitan and Pulau Sipadan
(Indonesia v. Malaysia
Judgment of 17 December 2002

[p. D.O. Franck] 43. In the present case, this Court might have built on the Lausanne and Preah Vihear precedents to confirm the legal presumption in favour of the dispositiveness of frontiers defined in a treaty, i.e., that, when a treaty is made for the purpose of defining a boundary, it should be construed, if possible, to have succeeded in doing so to the full extent of the interface between the parties, unless there is persuasive evidence that some areas were meant to be exempt from its allocation. The onus of proving the intent to create such an exemption, however, should lie with the party asserting it.

44. Presumptions are necessary and well-established aspects both of common and civil law and cannot but be a part of the fabric of public international law. They capture the common experience of persons everywhere that make inferences an essential part of rational thought and action. As such, they are often captured in legal maxims recognized across diverse legal systems (Henri Roland, Laurent Boyer, Adages du droit français, 3rd ed., 1992, p. 38; and see examples indexed under the title “Presomption” at p. 1009.) As Professor Bin Cheng has pointed out:

“Without going so far as to holding them to be true, it is legitimate for a tribunal to presume the truth of certain facts or of a certain state of affairs, leaving it to the party alleging the contrary to establish its contention. These presumptions serve as initial premises of legal reasoning.” (Bin Cheng, General Principles of Law as Applied by International Courts and Tribunals, 1987, p. 304.)

“In general, it may be said that what is normal, customary or the more probable is presumed, and that anything to the contrary has to be proved by the party alleging it.” (Ibid., p. 306).

The same point, citing various instances, is made by Professor Thirlway:

“presumptions can and do play an important part in directing the reasoning of a tribunal ... in the delicate operation of ascertainment of the intention of one or more States ... This results from the fact that direct circumstantial evidence of an intention may be very hard to come by, or may in the nature of things not exist.” (H. W. A. Thirlway, “Evidence before International Courts in Tribunals”, in Encyclopedia of Public International Law, Vol. Two, 1995, p. 303.)

45. In the present case, there is circumstantial evidence that the Parties thought they were resolving all the territorial problems arising out of their overlapping imperial claims in the Borneo area. Even were that evidence inconclusive, it is surely sufficient to invoke the rebuttable presumption, based on the commonsense and experience of diplomacy and recognized by several international tribunals, to the effect that when States negotiate a boundary allocating or confirming their respective areas of sovereignty over territories, these shall be presumed to have intended to resolve all outstanding and potentially disputatious claims in the area in question, subject only to convincing evidence to the contrary.

46. If the Court had applied this legal presumption to the Indonesia-Malaysia dispute, it would have concluded, as I do, that the 1891 Convention intended Ligitan and Sipadan to be Dutch and, now, Indonesian.