Blockade

A blockade is the act of using military force to prevent a country or region from receiving or sending goods. These goods can include food, weapons, supplies, or communications. It can also be used to stop the movement of people. A blockade is different from an embargo or a sanction. Embargoes and sanctions are legal barriers to trade. In contrast, a blockade uses physical barriers to control movement. While most blockades happen at sea, they can also occur on land or in the air.

Blockades function through several different methods of control. A close blockade involves placing warships within sight of a coast or port. This method is very effective but also very difficult to maintain. Sailors must endure storms and stay at sea far from support. They also face the risk of sudden attacks from enemy ships hiding in harbors. A distant blockade is different because the ships stay far away from the coast. They attempt to intercept vessels in the open ocean instead. This method allows ships to stay closer to their home bases.

A third method is known as a loose blockade. In this setup, blockading ships stay just out of sight behind the horizon. The goal is to lure enemy ships out into the open to strike them. Admiral Horatio Nelson used this tactic at Cádiz in 1805. This led to the famous Battle of Trafalgar. In the modern era, blockades have expanded to include air and electronic space. Air power can halt traffic within a specific airspace. Electronic blockades can involve jamming radio signals or severing undersea cables.

History shows that blockades have changed how wars are fought. For millennia, primitive naval blockades were used, but they were limited by ship technology. The British Royal Navy achieved the first successful full naval blockades during the Seven Years' War from 1754 to 1763. Admiral Edward Hawke extended a blockade along the entire French Atlantic coast. This weakened the French economy and helped the British gain Canada in 1763. The Royal Navy continued to use this strategy during the Napoleonic Wars from 1803 to 1815.

Many major conflicts relied on the strategic use of blockades. During the American Civil War from 1861 to 1865, the Union blockaded southern ports. In World War I, the Allies blockaded the Central Powers to deprive them of food and materials. Germany attempted to use U-boats to blockade Britain, but this effort ultimately failed. During World War II, German U-boats tried a similar distant blockade against the United Kingdom. Naval thinkers like Alfred Thayer Mahan and Julian Corbett argued that blockades were essential for winning naval conflicts.

Planning a successful blockade requires four specific factors. First, the item being blocked must be valuable enough to justify the effort. For example, during the 1962 Cuban Missile Crisis, President Kennedy used a blockade to stop nuclear missiles. Second, the blockading force must be stronger than the opposition. Third, the blockade must actually succeed in stopping the target items. Finally, geography is vital because certain areas like straits act as natural choke points.

Modern international law treats a blockade as an act of war. It is only legal when used for self-defense and not for aggression. The United Nations Security Council can also apply blockades under the UN Charter. There are strict rules regarding what can be considered "contraband," or forbidden goods. A blockading nation must publish its list of contraband. While they can inspect ships in international waters, they cannot enter the territorial waters of neutral nations. If a ship refuses to stop for inspection, it can be captured.

Blockades carry heavy consequences for human populations. They can result in the starvation of civilians, as seen in Germany during World War I and in Biafra during the Nigerian Civil War. Because of this, using a blockade to starve or punish a civilian population is a war crime. It may even be considered a crime against humanity. To bypass these restrictions, some use "blockade runners." These are fast, lightly armed ships used to deliver cargo. In other cases, such as the Berlin Blockade, aircraft were used to create airbridges to deliver supplies.