The Eritrea-Yemen arbitration: Landmark progress in the acquisition of territorial sovereignty and equitable maritime boundary delimitation

The Eritrea-Yemen Arbitral Tribunal unanimously resolved in its two awards the disputed territorial sovereignty over the Red Sea islands (Phase I, 199 8) and the delimitation of an international maritime boundary (Phase II, 19 99) in one of the most strategically sensitive regions of the world. This article surveys the progress made by each of the awards in the develop ment of principles and rules of international law in the respective subject matters of the awards. While due attention is paid to the consistency of t he awards with the preceding decisions of the International Court of Justic e and arbitral tribunals concerning acquisition of territorial sovereignty and equitable maritime delimitation, distinct features, such as rejection b y the 1998 Eritrea-Yemen Award of the existence of a principle of reversion of a newly independent state to the ancient title to territory, are also e xamined. The analysis of the 1999 Award focuses on the complex decision-mak ing process which led the Arbitral Tribunal to equitable delimitation of th e Eritrea-Yemen international maritime boundary by means of a single all-pu rpose boundary. The resultant line substantiates the governing role of equi distance between opposite states. The Tribunal also reappraised the role of resource-related factors and the principle of proportionality.