Territorial sea - Casus belli

The breadth of Greece’s territorial sea was set at 6 nautical miles from the natural coastline in 1936 (Law 230/1936 as amended by Presidential Decree 187/1973).  However, the limit of 10 nautical miles of territorial sea regarding national airspace was explicitly maintained, based on previous legislation (Decree of 6 September 1931 in conjunction with Law 5017/1931).

According to customary international law, which is also codified in the UN Convention on the Law of the Sea (UNCLOS), Greece has the right to extend its territorial waters to 12 nautical miles.

This right to extend territorial waters to up to 12 nautical miles is a sovereign right which can be unilaterally exercised, and is therefore not subject to any kind of restriction or exception and cannot be disputed by third countries (Article 3 of UNCLOS, which codifies a rule of customary law, does not provide for any restrictions or exceptions with regard to this right). The overwhelming majority of coastal states, except for a few exceptions, have determined the breadth of their territorial sea at 12 nautical miles.  Türkiye itself has extended its territorial waters to 12 nautical miles in the Black Sea and the Mediterranean already since 1964.

During ratification of the United Nations Convention on the Law of the Sea (Law 2321/1995), our country stated explicitly that it reserves the right to exercise this right at any point in time. In this regard, it should be noted that Greece has already extended by law its  territorial see to 12 nautical miles in the Ionian Sea, while as explicitly stated in Art. 2 of Law No. 4767/2021, whereby this extension took place, “The Hellenic Republic reserves the right to exercise in other areas of its territory its respective rights, as derived from the United Nations Convention on the Law of the Sea, which also reflects customary international law”.

Casus Belli

In reaction to this legitimate declaration of Greece upon the ratification of the Convention of the Law of the Sea (Law No. 2321/1995) that it reserves the right to exercise at any time its right to extend its territorial sea up to 12 nautical miles, the Turkish National Assembly issued a resolution on 8 June 1995 granting the Turkish government full and perpetual competence to declare war (casus belli) (authorizing it to use military means against Greece), should Greece decide to extend its territorial waters over 6 nautical miles in the Aegean.

This stance on the part of Türkiye is a blatant violation of the fundamental principles of the UN Charter on refraining from the threat or use of force (article 2, paragraph 4), on the peaceful resolution of disputes (article 2 paragraph 3) and on good neighbourly relations and peaceful coexistence (Preamble).

It concurrently undermines the allied relations which should exist between states belonging to the same Alliance and goes against the basic principles on which NATO is founded (articles 1 and 2 of the North Atlantic Treaty).

The withdrawal of the casus belli against Greece has been included in the basic criteria set for Türkiye’s accession to the European Union as part of its obligation to fully respect international law and good neighbourly relations, one of the fundamental principles on which the European Union is founded. It is obvious that a candidate member state cannot threaten war against another state, not least an EU member state and future partner.

This is also a necessary prerequisite for substantial improvement in Greek-Turkish relations and for easing tensions. It is obvious that efforts to iron out points of friction and peacefully resolve disputes cannot be effective under the threat of war.