It must be specially observed that no legal duty exists for the attacking forces to restrict bombardment to fortifications only. On the contrary, destruction of private and public buildings through bombardment has always been and is still considered lawful, as it is one of the means to impress upon the authorities the advisability of surrender. Some writers[306] assert either that bombardment of the town, in contradistinction to the fortifications, is never lawful, or that it is only lawful when bombardment of the fortifications has not resulted in inducing surrender. But this opinion does not represent the actual practice of belligerents, and the Hague Regulations do not adopt it.
[306] See, for instance, Pillet, pp. 104-107; Bluntschli § 554A; Mérignhac, p. 180. Vattel (III. § 169) does not deny the right to bombard the town, although he does not recommend such bombardment.
X ESPIONAGE AND TREASON
Vattel, III. §§ 179-182—Hall, § 188—Westlake, II. pp. 79 and 90—Lawrence, § 199—Phillimore, III. § 96—Halleck, I. pp. 571-575, and in A.J. V.(1911), pp. 590-603—Taylor, §§ 490 and 492—Wharton, III. § 347—Moore, VII. § 1132—Bluntschli, §§ 563-564, 628-640—Heffter, § 125—Lueder in Holtzendorff, IV. pp. 461-467—Ullmann, § 176—Bonfils, Nos. 1100-1104—Despagnet, Nos. 537-542—Pradier-Fodéré, VI. Nos. 2762-2768—Rivier, II. pp. 282-284—Nys, III. pp. 256-263—Calvo, IV. §§ 2111-2122—Fiore, III. Nos. 1341, 1374-1376, and Code, Nos. 1487-1490—Martens, II. § 116—Longuet, §§ 63-75—Mérignhac, pp. 183-209—Pillet, pp. 97-100—Zorn, pp. 174-195—Holland, War, Nos. 84-87—Bordwell, pp. 291-292—Meurer, §§ 35-38—Spaight, pp. 202-215, 333-335—Ariga, §§ 98-100—Takahashi, pp. 185-194—Friedemann, Die Lage der Kriegskundschafter und Spione (1892)—Violle, L'espionage militaire en temps de guerre (1904)—Adler, Die Spionage (1906)—Kriegsbrauch, pp. 30-31—Land Warfare, §§ 155-173—Bentwich in The Journal of the Society of Comparative Legislation, New Series, X. (1909), pp. 243-299.
Twofold Character of Espionage and Treason.
§ 159. War cannot be waged without all kinds of information about the forces and the intentions of the enemy and about the character of the country within the zone of military operations. To obtain the necessary information, it has always been considered lawful, on the one hand, to employ spies, and, on the other, to make use of the treason of enemy soldiers or private enemy subjects, whether they were bribed[307] or offered the information voluntarily and gratuitously. Article 24 of the Hague Regulations enacts the old customary rule that the employment of methods necessary to obtain information about the enemy and the country is considered allowable. The fact, however, that these methods are lawful on the part of the belligerent who employs them does not prevent the punishment of such individuals as are engaged in procuring information. Although a belligerent acts lawfully in employing spies and traitors, the other belligerent, who punishes spies and traitors, likewise acts lawfully. Indeed, espionage and treason bear a twofold character. For persons committing acts of espionage or treason are—as will be shown below in § [255]—considered war criminals and may be punished, but the employment of spies and traitors is considered lawful on the part of the belligerents.
[307] Some writers maintain, however, that it is not lawful to bribe enemy soldiers into espionage; see below, § [162].
Espionage in contradistinction to Scouting and Despatch-bearing.
§ 160. Espionage must not be confounded, firstly, with scouting, or secondly, with despatch-bearing. According to article 29 of the Hague Regulations, espionage is the act of a soldier or other individual who clandestinely, or under false pretences, seeks to obtain information concerning one belligerent in the zone of belligerent operations with the intention of communicating it to the other belligerent.[308] Therefore, soldiers not in disguise, who penetrate into the zone of operations of the enemy, are not spies. They are scouts who enjoy all privileges of the members of armed forces, and they must, if captured, be treated as prisoners of war. Likewise, soldiers or civilians charged with the delivery of despatches for their own army or for that of the enemy and carrying out their mission openly are not spies. And it matters not whether despatch-bearers make use of balloons or of other means of communication. Thus, a soldier or civilian trying to carry despatches from a force besieged in a fortress to other forces of the same belligerent, whether making use of a balloon or riding or walking at night, may not be treated as a spy. On the other hand, spying can well be carried out by despatch-bearers or by persons in a balloon, whether they make use of the balloon of a despatch-bearer or rise in a balloon for the special purpose of spying.[309] The mere fact that a balloon is visible does not protect the persons using it from being treated as spies; since spying can be carried out under false pretences quite as well as clandestinely. But special care must be taken really to prove the fact of espionage in such cases, for an individual carrying despatches is prima facie not a spy and must not be treated as a spy until proved to be such.
[308] Assisting or favouring espionage or knowingly concealing a spy are, according to a customary rule of International Law, punishable as though they were themselves acts of espionage; see Land Warfare, § 172.