A blockade is the act of actively preventing a country or region from receiving or sending out

food Food is any substance consumed by an organism for nutritional support. Food is usually of plant, animal, or fungal origin, and contains essential nutrients, such as carbohydrates, fats, proteins, vitamins, or minerals. The substance is inge ...

, supplies, weapons, or communications, and sometimes people, by military force. A blockade differs from an embargo or sanction, which are legal barriers to trade rather than physical barriers. It is also distinct from a siege in that a blockade is usually directed at an entire country or region, rather than a fortress or city and the objective may not always be to conquer the area. While most blockades historically took place at sea, blockades are also used on land to prevent entrance of an area. For example, Armenia is a landlocked country that Turkey and Azerbaijan blockade. Thus, Armenia cannot conduct international trade through those countries, and mainly trades through Georgia. This restricts the country's economic development. A blockading power can seek to cut off all maritime transport from and to the blockaded country; although stopping all land transport to and from an area may also be considered a blockade. Blockades restrict the trading rights of neutrals, who must submit for inspection for contraband, which the blockading power may define narrowly or broadly, sometimes including food and medicine. In the 20th century,

air power Airpower or air power consists of the application of military aviation, military strategy and strategic theory to the realm of aerial warfare and close air support. Airpower began in the advent of powered flight early in the 20th century. Airpo ...

has also been used to enhance the effectiveness of the blockade by halting air traffic within the blockaded airspace. Close patrol of hostile ports, in order to prevent naval forces from putting to sea, is also referred to as a blockade. When coastal cities or fortresses were besieged from the landward side, the besiegers would often blockade the seaward side as well. Most recently, blockades have sometimes included cutting off electronic communications by jamming radio signals and severing

undersea cables Submarine cable is any electrical cable that is laid on the seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the ...

History

Although primitive naval blockades had been in use for millennia, the first successful attempts at establishing a full naval blockade were made by the British Royal Navy during the Seven Years' War (1754–1763) against France. Following the British naval victory at Quiberon Bay, which ended any immediate threat of a major

invasion of Britain The term Invasion of England may refer to the following planned or actual invasions of what is now modern England, successful or otherwise. Pre-English Settlement of parts of Britain * The 55 and 54 BC Caesar's invasions of Britain. * The 43 AD ...

, Britain established a close blockade on the French coast. This starved French ports of commerce, weakening France's economy. Admiral Edward Hawke took command of the blockading fleet off Brest and extended the blockade to cover the entire French Atlantic coast from

Dunkirk Dunkirk (french: Dunkerque ; vls, label=French Flemish, Duunkerke; nl, Duinkerke(n) ; , ;) is a commune in the department of Nord in northern France.Bordeaux, and also to

Marseilles Marseille ( , , ; also spelled in English as Marseilles; oc, Marselha ) is the prefecture of the French department of Bouches-du-Rhône and capital of the Provence-Alpes-Côte d'Azur region. Situated in the camargue region of southern Franc ...

on France's Mediterranean coast. The strategic importance of blockade was shown during the French Revolutionary Wars and Napoleonic Wars, when the Royal Navy successfully blockaded France, leading to major economic disruptions. The Union blockade of southern ports was a major factor in the American Civil War During World War I, the Allies blockaded the Central Powers, depriving them of food and other strategic materials. Germany's attempted U-boat blockade caused some shortages in Britain, but ultimately failed. This outcome was repeated in World War II. Naval strategic thinkers, such as Sir Julian Corbett and Alfred Thayer Mahan, wrote that naval conflicts were won primarily by decisive battles, and but also by blockade.

Types of blockade

Close, distant, and loose blockades

A ''close'' blockade entails placing warships within sight of the blockaded coast or port, to ensure the immediate interception of any ship entering or leaving. It is both the most effective and the most difficult form of blockade to implement. Difficulties arise because the blockading ships must remain continuously at sea, exposed to storms and hardship, usually far from any support, and vulnerable to sudden attack from the blockaded side, whose ships may stay safe in harbor until they choose to come out. In a ''distant'' blockade, the blockaders stay well away from the blockaded coast and try to intercept any ships going in or out. This may require more ships on station, but they can usually operate closer to their bases, and are at much less risk from enemy raids. This was almost impossible prior to the 16th century due to the nature of the ships used. A ''loose'' blockade is a close blockade where the blockading ships are withdrawn out of sight from the coast (behind the horizon) but no farther. The object of loose blockade is to lure the enemy into venturing out but to stay close enough to strike. British

admiral Admiral is one of the highest ranks in some navies. In the Commonwealth nations and the United States, a "full" admiral is equivalent to a "full" general in the army or the air force, and is above vice admiral and below admiral of the fleet, ...

Horatio Nelson Vice-Admiral Horatio Nelson, 1st Viscount Nelson, 1st Duke of Bronte (29 September 1758 – 21 October 1805) was a British flag officer in the Royal Navy. His inspirational leadership, grasp of strategy, and unconventional tactics brought abo ...

applied a loose blockade at Cádiz in 1805. The Franco-Spanish fleet under Pierre-Charles Villeneuve then came out, resulting in the Battle of Trafalgar.

Pacific blockade

Until 1827, blockades, as part of economic warfare, were always a part of a war. This changed when France, Russia and Britain came to the aid of the Greek rebels against Turkey. They blockaded the Turkish-occupied coast, which led to the

battle of Navarino The Battle of Navarino was a naval battle fought on 20 October (O. S. 8 October) 1827, during the Greek War of Independence (1821–29), in Navarino Bay (modern Pylos), on the west coast of the Peloponnese peninsula, in the Ionian Sea. Allied fo ...

. War was never declared, however, so it is considered the first ''pacific'' — i.e. peaceful — blockade. The first truly

pacific blockade A pacific blockade is a blockade exercised by a great power for the purpose of bringing pressure to bear on a weaker state without actual war. It can be employed only as a measure of coercion by maritime powers able to bring into action such vas ...

, involving no shooting at all, was the British blockade of the Republic of New Granada in 1837, established to compel New Granada to release an imprisoned British consul.

Legal status

President Kennedy with advisors after EXCOMM meeting, 29 October 1962 crop

Since 1945, the United Nations Security Council determines the legal status of blockades and by article 42 of the UN Charter, the council can also apply blockades. The UN Charter allows for the right of self-defense but requires that this must be immediately reported to the Security Council to ensure the maintenance of international peace. According to the not ratified document

San Remo Manual The San Remo Manual on International Law Applicable to Armed Conflicts at Sea was adopted in June 1994 by the International Institute of Humanitarian Law after a series of round table discussions held between 1988 and 1994 by diplomats and naval and ...

on International Law Applicable to Armed Conflicts at Sea, 12 June 1994, a blockade is a legal method of warfare at sea but is governed by rules. The manual describes what can never be contraband. The blockading nation is free to select anything else as contraband in a list, which it must publish. The blockading nation typically establishes a blockaded area of water, but any ship can be inspected as soon as it is established that it is attempting to break the blockade. This inspection can occur inside the blockaded area or in international waters, but never inside the territorial waters of a neutral nation. A neutral ship must obey a request to stop for inspection from the blockading nation. If the situation so demands, the blockading nation can request that the ship divert to a known place or harbour for inspection. If the ship does not stop, then the ship is subject to capture. If people aboard the ship resist capture, they can be lawfully attacked.

Act of war

Whether or not a blockade was seen as lawful depended on the laws of the nations whose trade was influenced by the blockade. The Brazilian blockade of Río de la Plata in 1826 during the Cisplatine War, for instance, was considered lawful according to British law but unlawful according to French and American law. The latter two countries announced they would actively defend their ships against Brazilian blockaders, while Britain was forced to steer for a peaceful solution between Brazil and Argentina.Sondhaus, Lawrence. 2004. "Navies in Modern World History", p. 98. .

Civil disobedience

Embracing the base, Greenham Common December 1982 - geograph

There are a number of protest actions with the specific aim of cutting off material, people or communications from a particular area, either in part or totally. The effectiveness of such blockades rely on the participation of people and lock-on techniques. A

sit-down strike A sit-down strike is a labour strike and a form of civil disobedience in which an organized group of workers, usually employed at factories or other centralized locations, take unauthorized or illegal possession of the workplace by "sitting do ...

is a form of civil disobedience in which an organized group of workers, usually employed at a factory or other centralized location, take possession of the workplace by "sitting down" at their stations, effectively preventing their employers from replacing them with strikebreakers. A nonviolent picket is another example; it also illustrates the specificity of the blockade. Pickets may demand the blocking of some traffic while allowing other traffic; e.g. workers but not the customers, or customers but not workers. The Mau movement was a nonviolent movement for Samoan independence from colonial rule during the early 1900s. Amongst other actions, participants formed their own "police force",

picketing Picketing is a form of protest in which people (called pickets or picketers) congregate outside a place of work or location where an event is taking place. Often, this is done in an attempt to dissuade others from going in (" crossing the pick ...

stores in Apia to prevent the payment of customs to the authorities. Some other examples are the perimeter blockade by human chain at Greenham Common Women's Peace Camp, the blockade of the Franklin River dam site, and the Keystone Pipeline.

Blockade planning

Blockade connecticut plan civil war cartoon

Blockades depend on four general factors: * The value of the item being blockaded must warrant the need to blockade. For example, during the 1962

Cuban Missile Crisis The Cuban Missile Crisis, also known as the October Crisis (of 1962) ( es, Crisis de Octubre) in Cuba, the Caribbean Crisis () in Russia, or the Missile Scare, was a 35-day (16 October – 20 November 1962) confrontation between the United S ...

, the items to be blockaded (or " quarantined" to use the more neutral term selected by President John F. Kennedy) were

Medium-range ballistic missile A medium-range ballistic missile (MRBM) is a type of ballistic missile with medium range, this last classification depending on the standards of certain organizations. Within the U.S. Department of Defense, a medium-range missile is defined by ...

s, capable of delivering nuclear weaponry, bound for Cuba. Their value was high, as a military threat against the United States. * The strength of the blockading force must be equal to or greater in strength than the opposition. The blockade is only successful if the 'thing' in question is prevented from reaching its receiver. For example, the overwhelming power of the Royal Navy allowed a successful

blockade of Germany The Blockade of Germany, or the Blockade of Europe, occurred from 1914 to 1919. The prolonged naval blockade was conducted by the Allies of World War I, Allies during and after World War I in an effort to restrict the maritime supply of goods t ...

. * Geography. Knowing the routes of the enemy will help the blockader choose where to blockade: for example, a high

mountain pass A mountain pass is a navigable route through a mountain range or over a ridge. Since many of the world's mountain ranges have presented formidable barriers to travel, passes have played a key role in trade, war, and both Human migration, human a ...

or a

strait A strait is an oceanic landform connecting two seas or two other large areas of water. The surface water generally flows at the same elevation on both sides and through the strait in either direction. Most commonly, it is a narrow ocean channe ...

is a natural choke point and a candidate for fortification. * A blockade tends to be a long

campaign Campaign or The Campaign may refer to: Types of campaigns * Campaign, in agriculture, the period during which sugar beets are harvested and processed * Advertising campaign, a series of advertisement messages that share a single idea and theme * B ...

requiring a long-term commitment by the blockading power. The Atlantic U-boat campaign of World War I and

Battle of the Atlantic The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade ...

were essentially about German blockades, and lasted nearly as long as their respective wars. The Imperial Japanese Navy, however, made only sporadic efforts at blockade during the

Pacific war The Pacific War, sometimes called the Asia–Pacific War, was the theater of World War II that was fought in Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the vast ...

, preferring to seek victory by fleet action.

Blockade running

Blockade running is the practice of delivering cargo (food, for example) to a blockaded area. It has mainly been done by ships (called

blockade runner A blockade runner is a merchant vessel used for evading a naval blockade of a port or strait. It is usually light and fast, using stealth and speed rather than confronting the blockaders in order to break the blockade. Blockade runners usuall ...

s) across ports under naval blockade. Blockade runners were typically the fastest ships available and often lightly armed and armored. However, it is now also been done by aircraft, forming airbridges, such as over the Berlin blockade after World War II.

References

*{{cite EB1911, wstitle=Blockade Law of the sea Military strategy Military operations by type Economic warfare tactics