contraband, in international law, goods necessary or useful in the prosecution of war that a belligerent may lawfully seize from a neutral who is attempting to deliver them to the enemy. The term is sometimes also applied to the goods carried into a country by smuggling. The penalty for carrying contraband goods is the confiscation of the goods and often also of the vessel (see prize). Neutral ships guilty of direct assistance to the enemy may be treated as enemy ships. International law has not precisely defined all classes of goods that are contraband of war per se. Munitions are certainly absolute contraband, but the status of food and other conditional contraband at least indirectly needed for war is often in doubt. At the second (1907) of the Hague Conferences a vain attempt to define the classes of contraband was made. In World War I many powers at first agreed to abide by the terms of the Declaration of London (see London, Declaration of) respecting contraband, but in time unconditional blockade of all goods was adopted. At the beginning of World War II the belligerents drew up lists of absolute and conditional contraband, but the total absorption of the economy in warfare led to the prohibition, so far as possible, of all shipping to the enemy.
See P. C. Jessup, The Early Development of the Law of Contraband of War (1933).