Delusion and Error in Contracting Parties.
§ 500. Although a treaty was concluded with the real consent of the parties, it is nevertheless not binding if the consent was given in error, or under a delusion produced by a fraud of the other contracting party. If, for instance, a boundary treaty were based upon an incorrect map or a map fraudulently altered by one of the parties, such treaty would by no means be binding. Although there is freedom of action in such cases, consent has been given under circumstances which prevent the treaty from being binding.
III OBJECTS OF TREATIES
Vattel, II. §§ 160-162, 166—Hall, § 108—Phillimore, II. § 51—Walker, § 30—Bluntschli, §§ 410-416—Heffter, § 83—Ullmann, § 97—Bonfils, No. 819—Despagnet, No. 445—Pradier-Fodéré, II. Nos. 1080-1083—Mérignhac, II. p. 640—Rivier, II. pp. 57-63—Nys, III. p. 24—Fiore, II. Nos. 1001-1004, and Code, Nos. 755-758—Martens, I. § 110—Jellinek, "Die rechtliche Natur der Staatenverträge" (1880), pp. 59-60—Nippold, op. cit. pp. 181-190.
Objects in general of Treaties.
§ 501. The object of treaties is always an obligation, whether mutual between all the parties or unilateral on the part of one only. Speaking generally, the object of treaties can be an obligation concerning any matter of interest for States. Since there exists no other law than International Law for the intercourse of States with each other, every agreement between them regarding any obligation whatever is a treaty. However, the Law of Nations prohibits some obligations from becoming objects of treaties, so that such treaties as comprise obligations of this kind are from the very beginning null and void.[861]
[861] The voidance ab origine of these treaties must not be confounded with voidance of such treaties as are valid in their inception, but become afterwards void on some ground or other; see below, §§ [541]-544.
Obligations of Contracting Parties only can be Object.
§ 502. Obligations to be performed by a State other than a contracting party cannot be the object of a treaty. A treaty stipulating such an obligation would be null and void. But this must not be confounded with the obligation undertaken by one of the contracting States to exercise an influence upon another State to perform certain acts. The object of a treaty with such a stipulation is an obligation of one of the contracting States, and the treaty is therefore valid and binding.
An Obligation inconsistent with other Obligations cannot be an Object.