Why no treaty does not guarantee a balanced US fleet

Why might the US Navy retain an unbalanced or obsolete fleet when British no-treaty construction creates pressure to modernize?

Because construction still depends on Congress: Senate delays could interrupt the American response even as Britain resumed a familiar continuous-building pattern.

Much of the American 16-inch battleship surge came late in or just after the First World War, whereas Britain's Queen Elizabeth- and R-class surge had started earlier. Removing treaty limits creates competitive pressure but does not remove the US Senate from appropriations. Repeated congressional hesitation could leave American construction irregular while Britain simply returned to an established procurement rhythm. The answer distinguishes legal permission to build from the political ability to sustain a program.