Tensions in the East Mediterranean reached boiling point this week as Turkey began drilling just 75km off the west coast of Cyprus, well within the Republic of Cyprus exclusive economic zone (EEZ).

Cyprus’ EEZ claims, which are based on median distances from neighboring countries, have wide international acceptance. But not by Turkey, whose own maximalist claims are based on its definition of the continental shelf south of Anatolia.

Turkish drillship Fatih weighed anchor on 3 May,...