When is secession legitimate?

Secession claims are not sufficiently dealt with at international law. Similarly theoretical analyses of the moral justifications for secession widely differ, with little scholarly agreement on, for example, whether there is a primary right to secede, a remedial right only, or no right to secede at all. This paper reviews the scholarly debate on legal, moral and constitutional legitimacy of secession, and develops five criteria for assessing the overall legitimacy of a secession claim: (1) nationhood and claim to territory; (2) self-determination and autonomy; (3) treatment at the hands of the state; (4) viability of the proposed state ; and (5) position of the existing state. Applying these criteria to three very different but equally topical possible secession claims - Scotland from the United Kingdom, Catalonia from Spain, and Novorossiya from Ukraine - the interplay between these criteria is demonstrated.