Global trade routes and Washington Treaty constraints

The Royal Navy viewed imperial power through shipping routes and commercial movement rather than land area alone, making fast, far-ranging warships relevant to protection and interdiction. The trade map includes only vessels large enough to be visible at its scale, so the commercial system at risk was denser than the image suggests. Article 17 reflected American concern that belligerents might seize foreign warships under construction in their yards. The rule followed the First World War precedent in which ships being built in Britain could reinforce the Grand Fleet. The clause could declare another seizure illegal, but a paper restriction would work only if belligerents obeyed it.