MARE
DOMINIUM

Mare Liberum defended seas open to navigation and use. Yet the historical development of the law of the sea also records a long movement toward stronger coastal-state rights: wider territorial seas, continental-shelf rights and, eventually, the 200-nautical-mile exclusive economic zone.

An EEZ is not territorial sea. Under the law of the sea, the coastal state has specified sovereign rights and jurisdiction rather than full sovereignty, while other states retain important freedoms of navigation and overflight. That legal distinction must remain clear.

Strategically, however, a different tendency can be observed: states increasingly treat parts of their EEZs as security spaces closely tied to national defence, resources and strategic depth. In practice, the political sensitivity surrounding the EEZ can therefore move closer to the sensitivity historically associated with territorial waters, even though the legal regimes remain distinct.

This territorialising tendency should not be reduced to a simple appetite for maritime expansion. It can also be understood as a defensive response to the asymmetry embedded in hegemonic use of the open sea.

A naval hegemon benefits disproportionately from a maritime order in which its forces can move globally, conduct surveillance, approach foreign coasts and project power while invoking freedom of navigation. Coastal states that cannot compete symmetrically on the high seas have a structural incentive to push effective defence outward: to monitor, contest and, where possible, control the maritime approaches around them.

Seen from this perspective, disputes over military activity in EEZs and freedom-of-navigation operations are not only technical disagreements about legal interpretation. They are also manifestations of a deeper struggle over whose freedom the open sea materially serves, and where legitimate coastal defence ends and excessive restriction of common freedoms begins.

The transition can be expressed in three stages: legal jurisdiction → strategic territorialisation → effective control.

The first belongs to positive law. The second describes political and security behaviour: the tendency to imagine an adjacent maritime zone as part of national strategic space. The third depends on material capability. Satellites, unmanned systems, coastal missiles, seabed sensors, data fusion and persistent surveillance can turn a political claim to strategic depth into an increasingly enforceable reality.

Mare Dominium begins at this intersection. It does not claim that an EEZ legally becomes territorial sea. It asks whether the practical distinction between an open maritime space and a controlled maritime space can narrow even while the formal legal distinction remains intact.

The political desire to control maritime approaches is old. What is changing is the cost and feasibility of enforcing it. Persistent surveillance, autonomous systems, networked sensors and long-range precision weapons compress the distance between detection, identification and action.

This is why Mare Dominium is not merely another name for maritime jurisdiction. It describes the point at which a centuries-long tendency toward maritime territorialisation acquires a new technological foundation.

Mare Dominium does not require formal sovereignty over the sea, nor does it predict the disappearance of UNCLOS. Its central distinction is between juridical status and operational reality.

A ship may retain a legal right to navigate while surveillance, targeting, denial systems, insurance costs, electronic interference or military pressure alter whether and how that right can actually be exercised. The future contest may therefore be less about formally owning the sea than about determining the conditions under which others can use it.