Who gained most from the Washington Naval Treaty?

The Washington settlement was structurally uneven because the participating navies did not accept comparable gains and losses. The United States capped the Japanese building challenge and emerged as the dominant treaty power in the Pacific. Italy received formal parity with France, forcing French planners to choose between matching Italy in the Mediterranean and distributing ships across a global empire. France could do both only with British support, so the tonnage formula reinforced French dependence on British cooperation. Britain avoided the worst outcome sometimes attributed to the treaty, but still lacked the aggregate carrier tonnage and individual capital-ship allowances best suited to its worldwide commitments. Arms-control ratios could reshape alliances and strategic geography as much as fleets.