[327] See Land Warfare, § 343.
However this may be, as a rule occupation will be coincident with invasion. The troops march into a district, and the moment they get into a village or town—unless they are actually fighting their way—they take possession of the Municipal Offices, the Post Office, the Police Stations, and the like, and assert their authority there. From the military point of view such villages and towns are now "occupied." Article 42 of the Hague Regulations enacts that territory is considered occupied when it is actually placed under the authority of the hostile army, and that such occupation applies only to the territory where that authority is established and in a position to assert itself. This definition of occupation is not at all precise, but it is as precise as a legal definition of such kind of fact as occupation can be. If, as some publicists[328] maintain, only such territory were actually occupied, in which every part is held by a sufficient number of soldiers to enforce immediately and on the very spot the authority of an occupant, an effective occupation of a large territory would be impossible, since then not only in every town, village, and railway station, but also in every isolated habitation and hut the presence of a sufficient number of soldiers would be necessary. Reasonably no other conditions ought to be laid down as necessary to constitute effective occupation in war than those under which in time of peace a Sovereign is able to assert his authority over a territory. What these conditions are is a question of fact which is to be answered according to the merits of the special case. When the legitimate Sovereign is prevented from exercising his powers and the occupant, being able to assert his authority, actually establishes an administration over a territory, it matters not with what means and in what ways his authority is exercised. For instance, when in the centre of a territory a large force is established from which flying columns are constantly sent round the territory, such territory is indeed effectively occupied, provided there are no enemy forces present, and, further, provided these columns can really keep the territory concerned under control.[329] Again, when an army is marching on through enemy territory, taking possession of the lines of communication and the open towns, surrounding the fortresses with besieging forces, and disarming the inhabitants in open places of habitation, the whole territory left behind the army is effectively occupied, provided some kind of administration is established, and further provided that, as soon as it becomes necessary to assert the authority of the occupant, a sufficient force can within reasonable time be sent to the locality affected. The conditions vary with those of the country concerned. When a vast country is thinly populated, a smaller force is necessary to occupy it, and a smaller number of centres need be garrisoned than in the case of a thickly populated country. Thus, the occupation of the former Orange Free State and the former South African Republic became effective in 1901 some time after their annexation by Great Britain and the degeneration of ordinary war into guerilla war, although only about 250,000 British soldiers had to keep up the occupation of a territory of about 500,000 square miles. The fact that all the towns and all the lines of communication were in the hands and under the administration of the British army, that the inhabitants of smaller places were taken away into concentration camps, that the enemy forces were either in captivity or dispersed into comparatively small guerilla bands, and finally, that wherever such bands tried to make an attack, a sufficient British force could within reasonable time make its appearance, was quite sufficient to assert British authority[330] over that vast territory, although it was more than a year before peace was finally established.
[328] See, for instance, Hall, § 161. This was also the standpoint of the delegates of the smaller States at the Brussels Conference of 1874 when the Declaration of Brussels was drafted.
[329] This is not identical with so-called constructive occupation, but is really effective occupation. An occupation is constructive only if an invader declares districts as occupied over which he actually does not exercise control—for instance, when he actually occupies only the capital of a large province, and proclaims that he has thereby occupied the whole of the province, although he does not take any steps to exercise control over it.
[330] The annexation of the Orange Free State dates from May 24, 1900, and that of the South African Republic from September 1, 1900. It may well be doubted whether at these dates the occupation of the territories concerned was already so complete as to be called effective. The British Government ought not, therefore, to have proclaimed the annexation at such early dates. But there ought to be no doubt that the occupation became effective some time afterwards, in 1901. See, however, Sir Thomas Barclay in The Law Quarterly Review, XXI. (1905), p. 307, who asserts the contrary; see also, below, § [264, p. 326, note 2], and § [265, p. 327, note 1]. The Times' History of the War in South Africa (vol. V. p. 251) estimates the number of Boer fighters in May 1901 to be about 13,000. These armed men were dispersed into a very large number of guerilla bands, and they were in a great many cases men who seemingly had submitted to the British authorities, but afterwards had taken up arms.
It must be emphasised that the rules regarding effective occupation must be formulated on the basis of actual practice quite as much as rules regarding other matters of International Law. Those rules are not authoritative which are laid down by theorists, but only those which are abstracted from the actual practice of warfare and are unopposed by the Powers.[331]
[331] The question is so much controverted that it is impossible to enumerate the different opinions. Readers who want to study the question must be referred to the literature quoted above at the commencement of § 166.
Occupation, when ended.
§ 168. Occupation comes to an end when an occupant withdraws from a territory or is driven out of it. Thus, occupation remains only over a limited area of a territory if the forces in occupation are drawn into a fortress on that territory and are there besieged by the re-advancing enemy, or if the occupant concentrates his forces in a certain place of the territory, withdrawing before the re-advancing enemy. But occupation does not cease because the occupant, after having disarmed the inhabitants and having made arrangements for the administration of the country, is marching on to overtake the retreating enemy, leaving only comparatively few soldiers behind.
Rights and Duties in General of the Occupant.