While scholars agree that political legitimacy, or the legitimacy to rule, is sought by governing authorities, the concept itself is often considered to be problematically vague. This article explores how the very ambiguity of the concept of legitimacy may make it ‘good to think with’. Calling into question two problematic assumptions in discussions of legitimacy—whether legitimacy is the prerogative of state authorities, and whether legality is a necessary basis from which to make claims for legitimacy—this article uses the cases of two exiled governing authorities, for Western Sahara and Tibet, to examine how legitimate government can be produced in the absence of full legality as a recognised sovereign state. Attending to similarities an...