Canton of Valais v. Canton of Tessin

Abstract

Territory — Boundaries — Tacit agreement — Unilateral recognition — Continuous, effective and uncontested exercise of sovereignty — Critical date — Natural frontiers — Watershed lineSources of international law — Protest and acquiescence — Estoppel — Acquiescence in boundary disputeStates — Federal States and confederations — Application of international law in dispute between two States within a confederation — Boundary dispute between two Swiss cantonsRelationship of international law and municipal law — Customary international law — Application of international law in disputes between Swiss cantons — The law of Switzerland