§ 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]
[746] The Henrik and Maria (1799), 1 C. Rob. 146.
[747] The Rolla (1807), 6 C. Rob. 364.
[748] As regards the whole matter, see Fauchille, Blocus, pp. 68-73.
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 Japanese 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]
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.
[750] See, for instance, Kleen, I. § 131.
[751] See, for instance, Bluntschli, 831-832; Martens, II. § 124, Gessner, p. 181.