Different kinds of Non-hostile Relations.
§ 216. As through the outbreak of war all diplomatic intercourse and other non-hostile relations come to an end, it is obvious that non-hostile relations between belligerents must originate either from special rules of International Law or from special agreements between the belligerents.
No special rules of International Law which demanded non-hostile relations between belligerents existed in former times, but of late a few rules of this kind have arisen. Thus, for instance, release on parole[429] of prisoners of war creates an obligation on the part of the enemy not to re-admit the individuals concerned into the forces while the war lasts. And, to give another example, by article 4 of the Geneva Convention of 1906, and article 14 of the Hague Regulations—see also article 17 of Convention X. of the Second Peace Conference—it is the duty of either belligerent to return to the enemy, by his prisoner-of-war bureau, all objects of personal use, letters, jewellery, and the like found on the battlefield or left by those who died in hospital.[430] Non-hostile relations of this kind, however, need not be considered in this chapter, since they have already been discussed on several previous pages.
Non-hostile relations originating from special agreements of belligerents, so-called commercia belli, may either be concluded in time of peace for the purpose of creating certain non-hostile relations between the parties in case war breaks out, or they may be concluded during the actual time of war. Such non-hostile relations are created through passports, safe-conducts, safeguards, flags of truce, cartels, capitulations, and armistices. Non-hostile relations can also be created by peace negotiations.[431] Each of these non-hostile relations must be discussed separately.
Licences to Trade.
§ 217. Several writers[432] speak of non-hostile relations between belligerents created by licences to trade granted by a belligerent to enemy subjects either within certain limits or generally. It has been explained above, in § [101], that it is for Municipal Law to determine whether or not through the outbreak of war all trade and the like is prohibited between the subjects of belligerents. If the Municipal Law of one or both belligerents does contain such a prohibition, it is of course within the discretion of one or both of them to grant exceptional licences to trade to their own or the other belligerent's subjects, and such licences naturally include certain privileges. Thus, for instance, if a belligerent allows enemy subjects to trade with his own subjects, enemy merchantmen engaged in such trade are exempt from capture and appropriation by the grantor. Yet it is not International Law which creates this exemption, but the very licence to trade granted by the belligerent and revocable at any moment; and no non-hostile international relations between the belligerents themselves originate from such licences. The matter would be different if, either in time of peace for the time of war, or, during war, the belligerents agreed to allow certain trade between their subjects; but non-hostile relations originating from such an agreement would not be relations arising from a licence to trade, but from a cartel.[433]
[432] See, for instance, Hall, § 196; Halleck, II. pp. 343-363; Lawrence, § 214; Manning, p. 168; Taylor, § 512; Wheaton, §§ 409-410; Fiore, III. No. 1500; Pradier-Fodéré, VII. No. 2938.