How local defense fleets could destabilize Starfleet

A Federation in which populated worlds maintain their own defense forces while Starfleet controls capital ships would face a familiar arms-control problem. Treaty-like limits might keep local fleets below capital-ship strength so wealthy planets cannot coerce poorer members. Local cruisers could still be modernized more rapidly while centrally funded battleships remain too few and age in service. Restricting local ships to sublight speed creates a different problem because compliance would require intrusive inspections for hidden faster-than-light construction. Planetary shields, fixed defenses, and local interception ships could share routine protection without removing the need for central heavy forces. The historical analogy is an empire-and-dominion structure in which local navies supplied cruisers, destroyers, and sloops while the Royal Navy provided battleships and carriers. Federal defense can therefore distribute the burden while creating new sources of rivalry.