Naval treaties are intended to avoid the cost of war, so declaring war to punish a shipbuilding violation undermines their purpose. Economic sanctions are another option, but governments still need to persuade others that the breach justifies the penalty. Britain would struggle to build that coalition if Germany adds one battleship while the Royal Navy has about twenty capital ships in service or on order. Durable agreements must therefore be equitable enough that every participant gains more from compliance than defection. A treaty that produces an obvious winner may contain the seeds of its own later breakdown even when its paper limits are clear.
Notable Point · 1:51:04-1:54:20
Why naval treaties need legitimacy, not just limits
A treaty broken by one extra battleship is difficult to enforce when war defeats its purpose and sanctions look disproportionate to neutral observers.