Available open access digitally under CC-BY-NC-ND licence.The precarious status of contested states both reflects and begets conflict. From Taiwan to Western Sahara and from Nagorno-Karabakh to the Liberation Tigers of Tamil Eelam, contested states call into question the standard categories of international law that divide inside and outside, state and non-state, war and rebellion. They inevitably fall in-between them, while alternatively disputing and negotiating their applicabili...