How one navy leaving the treaty system affects everyone

What happens if France and Italy leave the naval treaty system over their incompatible requirements?

Britain would invoke escalation to meet the Italian fleet, and that change would let the United States and Japan expand as the wider treaty system broke down.

Treaty limits depended on several regional balances operating at once. If France or Italy walked away, Britain would have to respond because the Italian fleet directly affected Mediterranean requirements. Invoking an escalator clause for that problem would also release the United States and Japan to adjust their programs. The system could therefore unravel even when the original dispute was not in the Pacific. Japan's historical departure did not trigger an immediate full response because governments still hoped it might return, illustrating how political expectations delayed the formal mechanism.