[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 pass through several States between their sources and their mouths at the sea coast, if one or more upper riparian States remain neutral.
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.
[743] The matter is thoroughly treated by Fauchille, Blocus, pp. 13-36, and Güldenagel, op. cit. pp. 39-86.
[744] See Hautefeuille, II. pp. 190-191.
[745] See Gessner, p. 151; Bluntschli, § 827; Martens, II. § 124.
II ESTABLISHMENT OF BLOCKADE
See the literature quoted above at the commencement of § [368].
Competence to establish Blockade.