Blockade

Lore & Background

Primitive naval blockades have been used for millennia, but early attempts were limited by how long ships could stay at sea. Notable early examples include the Athenian blockade of Melos and the Dutch blockade of the Spanish Netherlands—both predate the British efforts of the Seven Years' War. During that war, the British Royal Navy blockaded French ports separately, such as Brest and the St. Lawrence, but could not maintain a single continuous close blockade from Dunkirk to Marseille. Admiral Edward Hawke's close blockade off Brest after the 1759 victory at Quiberon Bay was a significant achievement, but it did not extend across the entire French coast.

Blockades became strategically important during the French Revolutionary Wars and the Napoleonic Wars, when the Royal Navy successfully blockaded France, causing major economic disruptions. The Union blockade of southern ports was a major factor in the American Civil War. In World War I, the Allies blockaded the Central Powers, depriving them of food and strategic materials, while Germany's U-boat blockade of Britain caused some shortages but ultimately failed. A similar outcome followed in World War II.

Types of blockade include close, distant, and loose blockades. A close blockade places warships within sight of the coast for immediate interception but is difficult to maintain. A distant blockade keeps ships well away from the coast, reducing risk. A loose blockade withdraws ships behind the horizon to lure the enemy out. The concept of a 'pacific blockade'—a blockade without a declaration of war—has several claimed firsts, including the 1827 blockade of Turkish-occupied Greece by France, Russia, and Britain, and the 1837 British blockade of New Granada, but no single event is definitively established as the first.

Reader's Guide

Blockades have shaped the outcome of major conflicts by cutting off essential supplies and weakening economies. Their significance lies in their ability to apply pressure without direct conquest, as seen in the British blockade of France during the Napoleonic Wars and the Union blockade in the American Civil War. In the 20th century, air power enhanced blockades by halting air traffic, and modern blockades have included cutting electronic communications. The legal status of blockades is now determined by the United Nations Security Council under Article 42 of the UN Charter, and they are considered acts of war, legal only in self-defense. Blockades that starve or collectively punish civilians are war crimes. The effectiveness of a blockade depends on the value of the item blockaded, the strength of the blockading force, geography, and long-term commitment. Blockade running, using fast ships to deliver cargo to blockaded areas, has been a persistent countermeasure. The legacy of blockades includes both their strategic utility and their humanitarian consequences, as seen in the starvation during the blockade of Germany in World War I and the blockade of Biafra.

Did You Know?

• No single blockade is universally recognized as the first successful full naval blockade; early examples include the Athenian blockade of Melos and the Dutch blockade of the Spanish Netherlands.
• The first pacific blockade is disputed, with both the British blockade of New Granada in 1837 and the French blockade of Mexico in 1838 cited as candidates.
• Blockades traditionally refer to the physical interdiction of maritime or aerial movement; cutting off electronic communications is not a widely recognized or established definition in military history or international l
• Blockades that starve or collectively punish a civilian population are considered war crimes under modern international law.