Blockade

A blockade is an operation by a state or coalition to prevent the movement of ships, goods, or people into or out of a defined area, typically to weaken an adversary during armed conflict. Blockades are most commonly maritime, but can also target land routes or air corridors around a coastline or port. The term also encompasses economic or political measures that restrict trade, often described as sanctions, aimed at pressuring a government without direct military action.

In international law, blockades are treated as belligerent measures that require clear declaration and effective enforcement. A legally valid blockade is expected to be enforced with the intent to prevent ingress or egress and to be directed against a defined enemy territory or force. Neutral ships may be warned, searched, or intercepted, and contraband may be subject to seizure or denial of entry. The legality and proportionality of a blockade depend on its implementation and compliance with applicable treaties and humanitarian norms, including protections for civilians and essential goods.

Enforcement typically involves naval or coast guard forces patrolling the blocked area, issuing notices, inspecting vessels, and interdicting shipments that violate the blockade. Blockades may also be supported by other means, such as economic sanctions, financial restrictions, or dual-use controls that hinder the flow of goods that could be used for military purposes. Blockade operations can be costly and controversial, with civilian populations often bearing significant consequences.

Impact and assessment: Blockades aim to weaken an opponent but risk humanitarian harm and international condemnation if they are not conducted in accordance with law and necessity. Their use has evolved with political objectives, diplomacy, and the broader system of sanctions in peacetime and conflict.