A belligerent declaration of war binds all of its subjects, so that merchants of a belligerent state are forbidden from trading with the enemy. But when a neutral state declares neutrality, that act does not bind all subjects of the neutral state. Neutral merchants are free to trade with belligerents – even in contraband, at their own risk. This essay examines international negotiations over contraband during the first decade of the 1900s while highlighting, in particular, the contradiction between the wish to maintain belligerent rights to determine contraband and to capture it on the high seas and, at the same time, to uphold neutral rights of free trade, which meant protecting private property in trade, including contraband. This asymmetry of the rules of contraband demonstrated that war is not a relation exclusively between states and, as a consequence, some within the international community proposed making individuals subjects of international law or, as an alternative, making neutral states responsible for prohibiting their subjects from trading contraband.