Legal Definitions - de facto blockade

A de facto blockade is a type of blockade in international law. It occurs when a belligerent prevents access to or egress from an enemy's ports by stationing ships to intercept vessels trying to enter or leave those ports. To be binding, a blockade must be effective, meaning it must be maintained by a force sufficient to prevent access to ports.

For example, during the Cuban Missile Crisis in 1962, the United States established a de facto blockade of Cuba by stationing ships around the island to prevent Soviet ships from delivering missiles and other military supplies. This blockade was effective in preventing the delivery of these supplies and ultimately led to the resolution of the crisis.

Unlike a public blockade, which is established with formal notice to the governments of neutral nations, a de facto blockade can be established without a declaration of war. However, it must still be effective to be considered binding under international law.