Gotland showed why Baltic islands needed real garrisons

The Russian landing on Gotland met no regular garrison, and a locally raised levy armed largely with fowling pieces could not challenge trained troops. Russia left Swedish local personnel in place under a new governor until a Swedish admiral arrived with the fleet and recovered the island. The episode warns against leaving a strategic Baltic position without regular defenders, stores, or fortifications. Sea power gave Sweden an internal line of communication because roads and other infrastructure could not move comparable volumes around the theatre. The movement problem is compared with the American Civil War's use of railways, rivers, and seaborne supply, while the Baltic sea itself served as Sweden's internal route. When the water froze it became a marching surface, while in open seasons the fleet could move troops and supplies. Gotland and Sveaborg were defended access points that made the entire manoeuvre system work.