International Law. A Treatise
Chapter 131 : -- 369. A blockade is termed strategic if it forms part of other military operations d

-- 369. A blockade is termed strategic if it forms part of other military operations directed against the coast which is blockaded, or if it be declared in order to cut off supply to enemy forces on sh.o.r.e. In contradistinction to blockade strategic, one speaks of a commercial blockade, when a blockade is declared simply in order to cut off the coast from intercourse with the outside world, although no military operations take place on sh.o.r.e. That blockades commercial are, according to the present rules of International Law, as legitimate as blockades strategic, is not generally denied. But several writers[735] maintain that blockades purely commercial ought to be abolished as not in accordance with the guaranteed freedom of neutral commerce during war.

[Footnote 735: See Hall, -- 233.]

[Sidenote: Blockade to be Universal.]

-- 370. A blockade is really in being when vessels of all nations are interdicted and prevented from ingress or egress. Blockade as a means of warfare is admissible only in the form of a _universal_ blockade, that is--as article 5 of the Declaration of London stipulates--it "must be applied impartially to the vessels of all nations." If the blockading belligerent were to allow the ingress or egress of vessels of one nation, no blockade would exist.[736]

[Footnote 736: The _Rolla_ (1807), 6 C. Rob. 364; the _Franciska_ (1855), Spinks, 287. See also below, -- 382.]

On the other hand, provided a blockade is universal, a special licence of ingress or egress may be given to a special vessel and for a particular purpose,[737] and men-of-war of all neutral nations may be allowed to pa.s.s to and fro unhindered.[738] Thus, when during the American Civil War the Federal Government blockaded the coast of the Confederate States, neutral men-of-war were not prevented from ingress and egress. But it must be specially observed that a belligerent has a right to prevent neutral men-of-war from pa.s.sing through the line of blockade, and it is entirely within his discretion whether or not he will admit or exclude them; nor is he compelled to admit them all, even though he has admitted one or more of them.

[Footnote 737: This exception to the general rule is not mentioned by the Declaration of London, but I have no doubt that the International Prize Court would recognise it.]

[Footnote 738: Recognised by article 6 of the Declaration of London.]

[Sidenote: Blockade, Outwards and Inwards.]

-- 371. As a rule a blockade is declared for the purpose of preventing ingress as well as egress. But sometimes only ingress or only egress is prevented. In such cases one speaks of "Blockade inwards" and of "Blockade outwards" respectively. Thus the blockade of the mouth of the Danube declared by the Allies in 1854 during the Crimean War was a "blockade inwards," since the only purpose was to prevent supply reaching the Russian Army from the sea.[739]

[Footnote 739: The _Gerasimo_ (1857), 11 Moore, P.C. 88.]

[Sidenote: What Places can be Blockaded.]

-- 372. In former times it was sometimes a.s.serted that only ports, or even only fortified[740] ports, could be blockaded, but the practice of the States has always shown that single ports and portions of an enemy coast as well as the whole of the enemy coast may be blockaded. Thus during the American Civil War the whole of the coast of the Confederate States to the extent of about 2500 nautical miles was blockaded. And attention must be drawn to the fact, that such ports of a belligerent as are in the hands of the enemy may be the object of a blockade. Thus during the Franco-German War the French blockaded[741] their own ports of Rouen, Dieppe, and Fecamp, which were occupied by the Germans.

Article 1 of the Declaration of London indirectly sanctions the practice of the States by enacting that "a blockade must not extend beyond the ports and coasts belonging to or occupied by the enemy."

[Footnote 740: Napoleon I. maintained in his Berlin Decrees: "Le droit de blocus, d'apres la raison et l'usage de tous les peuples polices, n'est applicable qu'aux places fortes."]

[Footnote 741: See Fauchille, _Blocus_, p. 161.]

[Sidenote: Blockade of International Rivers.]

-- 373. It is a moot question whether the mouth of a so-called international river may be the object of a blockade, in case the riparian States are not all belligerents. Thus, when in 1854, during the Crimean War, the allied fleets of Great Britain and France blockaded the mouth of the Danube, Bavaria and Wurttemberg, which remained neutral, protested. When in 1870 the French blockaded the whole of the German coast of the North Sea, they exempted the mouth of the river Ems, because it runs partly through Holland. And when in 1863, during the blockade of the coast of the Confederate States, the Federal cruiser _Vanderbilt_ captured the British vessel _Peterhoff_[742] destined for Matamaros, on the Mexican sh.o.r.e of the Rio Grande, the American Courts released the vessel on the ground that trade with Mexico, which was neutral, could not be prohibited.

[Footnote 742: 5 Wallace, 49. See Fauchille, _Blocus_, pp. 171-183; Phillimore, III. -- 293A; Hall, -- 266; Rivier, II. p. 291.]

The Declaration of London would seem to settle the controversy only as regards one point. By enacting that "the blockading forces must not bar access to neutral ports or coasts," article 18 certainly prohibits the blockade of the whole mouth of a boundary river between a neutral and a belligerent State, as, for instance, the River Rio Grande in case of war with the United States of America, provided Mexico remained neutral. But no provision is made for the case of the blockade of the mouths of rivers, such as the Danube or the Rhine, for example, which pa.s.s through several States between their sources and their mouths at the sea coast, if one or more upper riparian States remain neutral.

[Sidenote: Justification of Blockade.]

-- 374. The question has been raised in what way blockade, which vests a belligerent with a certain jurisdiction over neutral vessels and which has detrimental consequences for neutral trade, could be justified.[743]

Several writers, following Hautefeuille,[744] maintain that the establishment of a blockade by a belligerent stationing a number of men-of-war so as to block the approach to the coast includes conquest of that part of the sea, and that such conquest justifies a belligerent in prohibiting ingress and egress of vessels of all nations. In contradistinction to this artificial construction of a conquest of a part of the sea, some writers[745] try to justify blockade by the necessity of war. I think, however, no special justification of blockade is necessary at all. The fact is that the detrimental consequences of blockade to neutrals stand in the same category as the many other detrimental consequences of war to neutrals. Neither the one nor the other need be specially justified. A blockade interferes indeed with the recognised principle of the freedom of the sea, and, further, with the recognised freedom of neutral commerce. But all three have developed together, and when the freedom of the sea in time of peace and war, and, further, when the freedom of neutral commerce became generally recognised, the exceptional restrictions of blockade became at the same time recognised as legitimate.

[Footnote 743: The matter is thoroughly treated by Fauchille, _Blocus_, pp. 13-36, and Guldenagel, _op. cit._ pp. 39-86.]

[Footnote 744: See Hautefeuille, II. pp. 190-191.]

[Footnote 745: See Gessner, p. 151; Bluntschli, -- 827; Martens, II. -- 124.]

II

ESTABLISHMENT OF BLOCKADE

See the literature quoted above at the commencement of -- 368.

[Sidenote: Competence to establish Blockade.]

-- 375. A declaration of blockade being "a high[746] act of sovereignty"

and having far-reaching consequences upon neutral trade, it is generally recognised not to be in the discretion of a commander of a naval force to establish blockade without the authority of his Government. Article 9 of the Declaration of London precisely enacts that "a Declaration of blockade is made by the blockading Power or by the naval authorities acting in its name." The authority of his Government to establish a blockade can be granted to a commander of a naval force purposely for a particular blockade, the Government ordering the commander of a squadron to blockade a certain port or coast. Or a Government can expressly delegate its power to blockade to a commander for use at his discretion.

And if operations of war take place at great distance[747] from the seat of Government and a commander finds it necessary to establish a blockade, the latter can become valid through his Government giving its immediate consent after being informed of the act of the commander. And, further, the powers vested in the hands of the supreme commander of a fleet are supposed to include the authority to establish a blockade in case he finds it necessary, provided that his Government acquiesces as soon as it is informed of the establishment of the blockade.[748]

[Footnote 746: The _Henrik_ and _Maria_ (1799), 1 C. Rob. 146.]

[Footnote 747: The _Rolla_ (1807), 6 C. Rob. 364.]

[Footnote 748: As regards the whole matter, see Fauchille, _Blocus_, pp.

68-73.]

[Sidenote: Declaration and Notification of Blockade.]

-- 376. A blockade is not in being _ipso facto_ by the outbreak of war.

And even the actual blocking of the approach to an enemy coast by belligerent men-of-war need not by itself mean that the ingress and egress of _neutral_ vessels are to be prohibited, since it can take place for the purpose of preventing the egress and ingress of _enemy_ vessels only. Continental writers, therefore, have always considered notification to be essential for the establishment of a blockade.

English, American, and j.a.panese writers, however, have not hitherto held notification to be essential, although they considered knowledge on the part of a neutral vessel of an existing blockade to be necessary for her condemnation for breach of blockade.[749]

[Footnote 749: See below, -- 384.]

But although Continental writers have always held notification to be essential for the establishment of blockade, they differed with regard to the kind of notification that is necessary. Some writers[750]

maintained that three different notifications must take place--namely, first, a local notification to the authorities of the blockaded ports or coast; secondly, a diplomatic or general notification to all maritime neutral States by the blockading belligerent; and, thirdly, a special notification to every approaching neutral vessel. Other writers[751]

considered only diplomatic and special notification essential. Others again[752] maintained that special notification to every approaching neutral vessel is alone required, although they recommended diplomatic notification as a matter of courtesy.

[Footnote 750: See, for instance, Kleen, I. -- 131.]

[Footnote 751: See, for instance, Bluntschli, 831-832; Martens, II. -- 124, Gessner, p. 181.]

[Footnote 752: See, for instance, Hautefeuille, II. pp. 224 and 226; Calvo, V. -- 2846; Fauchille, pp. 219-221.]

As regards the practice of States, it has always been usual for the commander who established a blockade to send a notification of the blockade to the authorities of the blockaded ports or coast and the foreign consuls there. It has, further, always been usual for the blockading Government to notify the fact diplomatically to all neutral maritime States. And some States, as France and Italy, have always ordered their blockading men-of-war to board every approaching neutral vessel and notify her of the establishment of the blockade. But Great Britain, the United States of America, and j.a.pan did not formerly consider notification to be essential for the inst.i.tution of a blockade.

They held the simple fact that the approach was blocked, and egress and ingress of neutral vessels actually prevented, to be sufficient to make the existence of a blockade known, and when no diplomatic notification had taken place, they did not seize a vessel for breach of blockade whose master had no actual notice of the existence of the blockade.

English,[753] American,[754] and j.a.panese[755] practice, accordingly, made a distinction between a so-called _de facto_ blockade on the one hand, and, on the other, a notified blockade.

[Footnote 753: The _Vrouw Judith_ (1799), 1 C. Rob. 150.]

[Footnote 754: See U.S. Naval War Code, articles 39-40.]

[Footnote 755: See j.a.panese Prize Law, article 30.]

The Declaration of London, when ratified, will create a common practice, for articles 8 to 12 represent an agreement of the Powers on the following points:--