§ 315. Some writers[584] maintain that no rights derive from neutrality for neutrals, and, consequently, no duties for belligerents, because everything which must be left undone by a belligerent regarding his relations with a neutral must likewise be left undone in time of peace. But this opinion has no foundation. Indeed, it is true that the majority of the acts which belligerents must leave undone in consequence of their duty to respect neutrality must likewise be left undone in time of peace in consequence of the territorial supremacy of every State. However, there are several acts which do not belong to this class—for instance, the non-appropriation of enemy goods on neutral vessels. And those acts which do belong to this class fall nevertheless at the same time under another category. Thus, a violation of neutral territory on the part of a belligerent for military and naval purposes of the war is indeed an act prohibited in time of peace, because every State has to respect the territorial supremacy of other States; but it is at the same time a violation of neutrality, and therefore totally different from other violations of foreign territorial supremacy. This becomes quite apparent when the true inwardness of such acts is regarded. For every State has a right to demand reparation for an ordinary violation of its territorial supremacy, but it need not take any notice of it, and it has no duty to demand reparation. Yet in case a violation of its territorial supremacy constitutes at the same time a violation of its neutrality, the neutral State has not only a right to demand reparation, but has a duty[585] to do so. For, if it did not, this would contain a violation of its duty of impartiality, because it would be favouring one belligerent to the detriment of the other.[586]
[584] Heffter, § 149; Gareis, § 88; Heilborn, System, p. 341.
[585] See, for instance, article 3 of Convention XIII. of the Second Peace Conference, which enacts:—"When a ship has been captured in the territorial waters of a neutral Power, such Power must, if the prize is still within its jurisdiction, employ the means at its disposal to release the prize with its officers and crew, and to intern the prize crew. If the prize is not within the jurisdiction of the neutral Power, the captor Government, on the demand of that Power, must liberate the prize with its officers and crew."
On the other hand, it has been asserted[587] that, apart from conventional neutrality, from which treaty obligations arise, it is incorrect to speak of duties deriving from neutrality, since at any moment during the war neutrals could throw up neutrality and become parties to the war. I cannot agree with this opinion either. That a hitherto neutral can at any moment throw up neutrality and take part in the war, is just as true as that a belligerent can at any moment during the war declare war against a hitherto neutral State. Yet this only proves that there is no duty to remain neutral, and no duty for a belligerent to abstain from declaring war against a hitherto neutral State. This is a truism which ought not to be doubted, and is totally different from the question as to what duties derive from neutrality so long as a certain State remains neutral at all. The assertion that such duties derive from neutrality is in no way inconsistent with the fact that neutrality itself can at any moment during the war come to an end through the beginning of war by either a neutral or a belligerent. This assertion only states the fact that, so long as neutrals intend neutrality and so long as belligerents intend to recognise such neutrality of third States, duties derive from neutrality for both belligerents and neutrals.
[587] See Gareis, § 88.
Contents of Duty of Impartiality.
§ 316. It has already been stated above, in § 294, that impartiality excludes such assistance and succour to one of the belligerents as is detrimental to the other, and, further, such injuries to one of the belligerents as benefit the other, and that it includes active measures on the part of neutrals for the purpose of preventing belligerents from making use of neutral territories and neutral resources for their military and naval purposes. But all this does not exhaust the contents of the duty of impartiality.
It must, on the one hand, be added that according to the present strict conception of neutrality the duty of impartiality of a neutral excludes all facilities whatever for military and naval operations of the belligerents, even if granted to both belligerents alike. In former times assistance was not considered a violation of neutrality, provided it was given to both belligerents in the same way, and States were considered neutral although they allowed an equal number of their troops to fight on the side of each belligerent. To-day this could no longer happen. From Conventions V. and XIII. of the Second Peace Conference, which deal with neutrality in land and sea warfare respectively, it becomes quite apparent that any facility whatever directly concerning military or naval operations, even if it consists only in granting passage over neutral territory to belligerent forces, is illegal, although granted to both belligerents alike. The duty of impartiality to-day comprises abstention from any active or passive co-operation with belligerents.
On the other hand, it must be added that the duty of impartiality includes the equal treatment of both belligerents regarding such facilities as do not directly concern military or naval operations, and which may, therefore, be granted or not to belligerents, according to the discretion of a neutral. If a neutral grants such facilities to one belligerent, he must grant them to the other in the same degree. If he refuses them to the one, he must likewise refuse them to the other.[588] Thus, since it does not, according to the International Law of the present day, constitute a violation of neutrality if a neutral allows his subjects to supply either belligerent with arms and ammunition in the ordinary way of trade, it would constitute a violation of neutrality to prohibit the export of arms destined for one of the belligerents only. Thus, further, if a neutral allows men-of-war of one of the belligerents to bring their prizes into neutral ports, he must grant the same facility to the other belligerent.