BLOCKADE (Fr. Wagner, to obstruct, block; bloc, block). The investment of an enemy's city, port, or seacoast. It may be military, in which case the object of the operation is to reduce the invested place, or commercial, for the purpose of shutting out neutral commerce from access to the blockaded port or coast.
The right to establish a blockade rests iu the general right which every belligerent power pos sesses of distressing its enemy and weakening the power of resistance. (See BELLIGERENT.) As such it imposes the obligation of observance upon a neutral. even though incidentally the neutral be injured by the cutting off of commercial rela tions. But the neutral need not employ preven tive measures; nor is the breach of a blookado a municipal offense which the blockading power may require the neutral to punish. The respon sibility of its maintenance belongs to the block ading belligerent. As a sovereign act, also, the proclamation and establishment of a blockade rests with the highest authority of a State. At the commencement of a blockade a delay is usually granted by comity to permit neutral vessels in port to sail, which during the American Civil War was fixed at fifteen days. Neutral men of-war on diplomatic errands and ships in dis tress are generally allowed entry. A neutral may insist that due notice of the blockade shall be given, and that the declaration be substantiated by a suitable force at the point affected.
The rules relating to blockades are a develop ment of the past hundred years. In 1504 Prus sia, in alliance with Napoleon, had seized Han over and declared her ports closed to England. The latter retaliated by proclaiming the coast from the Elbe to Brest under blockade. Napo leon in 1S06 issued the Berlin Decree, laying the whole British coast under blockade. England followed with the Orders in Council putting a blockade on the coast from the Elbe to Italy. These were mere 'paper blockades,' as neither power conk] actually cover the coasts with block ading squadrons; but they served to render any neutral liable to seizure who went from an Eng lish to a Continental port, or rice rersa. The subsequent development of commerce and the recognition of neutral rights finally led to the Declaration of Paris in 1856, which requires that a "blockade. to be binding, must be effective."
The 'United States was not a party to this con vention, but (luring the Civil War was the first one practically to enforce its rules. The Crimean War, the American Civil War, and the war be tween the United States and Spain for the libera tion of Cuba, furnish the best examples of mod ern blockades.
Three requirements are necessary to constitute valid capture for breach of blockade: (1) Due Notification; (2) in Effectire Blockade; (3) Breach of Blockade. (1) Notice may be given in two ways: by diplomatic announcement to neutral powers and by a warning at the block aded port usually inscribed upon the register of the ship seeking to enter. The French rule requires both. But the diplomatic notice, after a reasonable length of time, under modern condi tions of communication, implies presumptive knowledge of the blockade on the part of all ship owners. In the Civil War, on April 19, 1861, the ports from Smith Carolina to Texas were proclaimed in a state of blockade, and a week later this was extended to Virginia. Since at first an effective force actually invested but a small portion of the coast, it was customary to give notice at the harbo•-mouth as the ports were really closed. Thus it was little more than a paper blockade for some time. If the blockade is raised temporarily. as by the approach of an enemy's ilet or for any other cause, excepting storms, a new diplomatic notice is necessary. (2) The rule for an effective blockade was adopted to prevent the widespread inconveniences resulting from the so-called 'paper' or 'cabinet' blockade. The Declaration of Paris defines it as "main tained by a force sufficient really to prevent ac cess to the coast of an enemy." It requires that the evasion be made a dangerous act. Breach of Blockade.—To render a capture valid an actual attempt to break an effective blockade must appear. This may be evidenced by the ship's papers, her course, or the owner's instruc tions. The penalty for breach is confiscation of the ship and, unless proved innocent, the cargo also. But no punishment can be inflicted upon the crew. The doctrine of `continuous voyages' requires that though a ship may touch at a neutral port, if her eventual destination is a blockaded one, she is liable. This rule is applied with caution.