Lines on Water
I. The Dissolution of Mare Liberum
In 1609, Hugo Grotius published *Mare Liberum* ('The Free Sea'), arguing that the open oceans could neither be possessed nor bounded because water has no fixed physical boundaries and cannot be occupied by force. For over three centuries, sovereign maritime territory was restricted to the 'cannon-shot rule' (roughly 3 nautical miles from the shoreline).
The adoption of UNCLOS in 1982 radically dismantled Grotius's paradigm. By establishing 12-nautical-mile Territorial Seas, 24-nautical-mile Contiguous Zones, and 200-nautical-mile Exclusive Economic Zones (EEZs), UNCLOS partitioned over 138 million square kilometers of ocean space—roughly 38% of the global sea surface—into national resource monopolies.
II. The Geometry of the Baseline
The entire spatial legitimacy of a 200-nm EEZ hinges upon the coastal 'baseline'. Under Article 5 of UNCLOS, the normal baseline is the low-water line along the coast as marked on large-scale charts officially recognized by the coastal State. However, Article 7 permits 'straight baselines' across deeply indented coastlines or fringing islands.
In the South China Sea and East China Sea, minor coral atolls, rocks, and artificial sand installations have become geopolitical flashpoints because classification as an 'island' (Article 121(1)) generates a full 200-nm EEZ, whereas an 'uninhabitable rock' (Article 121(3)) generates only a 12-nm territorial sea, and a 'submerged low-tide elevation' generates zero sovereign waters.