BLOCKADE. The term blockade, prop erly used, involves a state of war. The so called pacific blockade is a form of reprisal or restraint short of war. A blockade is also distinct from domestic prohibition of inter course or closure ofrts. Blockade does not necessarily in later days have any relation to siege. In a general way, blockade is an attempt to cut off a port or coast of an enemy from maritime communication.
The idea as to what actually constitutes a blockade has varied according to the relation ship of the belligerents and in different wars. Prior to the 16th century blockades were some times proclaimed when one belligerent wished to apprehend commerce bound for certain ports of the other belligerent. Gradually the idea became more clear owing to the development of maritime commerce. A proclamation of 1630 mentions that it is in accord with ancient custom that neutral vessels and cargoes may be confiscated if going to, coming from or sail ing near the enemy ports "which are continu ally held blocked by vessels of war at great cost.D There were many departures from the principle set forth in 1630 and belligerents en deavored to obtain the advantages of a blockade without assuming the obligations of its main tenance. Usually, till the latter part of the 18th century, the belligerents proclaimed and en forced blockades somewhat arbitrarily, even going so far as to interdict any commerce with an enemy.
The action of the northern states of Europe in the armed neutrality of 1780, which was later approved by France, Spain and Austria, served to modify the extreme claims of bellig erents which had been developing. Article IV of the declaration of the armed neutrality stated *that in order to 'determine what char acterized a blockaded port, that name should be accorded only to a port where by act of the power making the attack vessels anchored suf ficiently near should make it dangerous to en ter.° In 1800 Russia and Sweden agreed that a notification to the neutral vessel by the block ading force was necessary in order to render the neutral vessel liable to penalty.
The recognition of neutral rights secured by the armed neutralities of 1780 and 1800 was not continued in the early years of the 19th century, when by decrees and orders in coun cil Napoleon and Great Britain tried to destroy all commerce. During the first half of the 19th century there was a tendency to extend the belligerent interference with commerce at the expense of neutrals. At times areas of great extent were declared blockaded and no considerable force was sent to maintain the blockade. In one case in 1816 the penalty of death by hanging at the yard-arm was men tioned for the master or other principal officers of a vessel entering prohibited area. Against the extreme extension of the area of blockade President Monroe in 1816 protested, and in following years other American Presidents pro tested, in general endeavoring to secure large liberty for neutrals. Proclamations were is sued by belligerents making the presence of military officers and merchants of the enemy on board, or presence within six miles of the coast with contraband on board evidence of intention on the part of a vessel to violate a blockade. In 1825 Brazil proposed to require
bonds from neutral vessels that they would not violate blockade. The United States replied that *A blockade must execute itself.° At tempts were made to establish blockades which would allow ships of certain nationalities to pass while closing the ports to others and to continue a blockade for two months after the treaty of peace. While there were such great variations in proclamations, the differences in application of the principles were even greater.
There seems, therefore, as regards blockade, ample reason for the statement in the Declara tion of Paris of 1856, signed by Austria, France, Great Britain, Prussia, Russia, Sardinia and Turkey, *That maritime law in time of war has long been the subject of deplorable It was the aim of this declaration to establish a *uniform doctrine° on certain points, among these, blockade. Accordingly the fourth article of the Declaration provides: *Blockades, in order to be binding, must be effective—that is to say, maintained by a force sufficient really to prevent access to the coast of the enemy.° The United States, China, Mexico and Spain did not become parties to this declaration. Questions soon arose in regaid to the inter pretation of this clause which it had been hoped would end many of the *deplorable disputes.° Apparently to make the clause more clear the British Admiralty Manual added "or, at any rate, to create evident danger to ships attempt ing ingress or egress.° The Civil War in the United States put some of the doctrines in regard to blockade to the test. The French had generally maintained that liability for violation of blockade was con ditioned upon notification of the blockade to a vessel approaching the line by a vessel of the blockading force. Great Britain and the United States had contended that a general public notification was sufficient. These ideas were therefore in conflict. Questions were raised as to the effectiveness of a blockade which depended upon the co-operation of shore batteries or upon the closing of certain navi gable channels by the sinking of vessels, stones or other obstructions. The extent of coast line which might be blockaded effectively by such forces as the Northern States had at their dis posal was in doubt. Great Britain in the case of the Helen in 1865 stated the British and American point of view at that time, saying, *There are several conditions to be observed in order to justify the seizure of a ship for breach of blockade. The blockade must be effectual and (save accidental interruption by weather) constantly enforced. The neutral vessel must be taken in delicto. The blockade must be en forced against all nations alike, including the belligerent one. When all the necessary con ditions are satisfied, then, by the usage of nations, the belligerent is allowed to capture and condemn neutral vessels without remon strance from the neutral state.° (1865, L. R. 1 A. & E. 1).