Under what conditions did international law permit neutrals to trade with belligerents, or nations at war? Multiple choice question. As long as the trade did not involve war supplies, it was permissible, regardless of whether it existed prior to the outbreak of hostilities. As long as the trade existed prior to the outbreak of war, it was permissible, whether it involved war supplies or not. International law did not permit neutrals to trade with belligerents in time of war. As long as the trade existed prior to the outbreak of war, and did not involve war supplies, it was permissible