Spheres of influence are easier to impose on land than at sea in this account. International movement at sea lets states choose where to send their ships, which complicates attempts to establish exclusive control over a maritime area. Excluding another state's ships therefore raises freedom-of-navigation questions. Maritime influence remains possible, but it cannot simply be treated as an exclusive territorial sphere.
Notable Point · 42:55-43:25
Spheres of influence and freedom of navigation
The distinction between land and sea explains why naval spheres of influence run into freedom-of-navigation disputes.