This is an open access title available under the terms of a CC BY-NC-ND 4.0 International license. It is free to read at Oxford Academic and offered as a free PDF download from OUP and selected open access locations. Political protest is often at least partially about the question of legitimacy. How can we distinguish whether a regime is legitimate, or merely purports to be so? In Facing Authority, Thomas Fossen develops a new philosophical approach to political legitimacy, interweaving analyses of key concepts (including representation, identity, and temporality) with examples of real-life struggles for legitimacy, from the German Autumn to the Arab Spring. Instead of asking "what makes authorities legitimate?" in the abstract, Fossen investigates how the question of legitimacy manifests itself in practice. Facing Authority proposes that judging legitimacy is not simply a matter of applying moral principles, but of engaging in various forms of political contestation: over the representation of power (what is the nature of the regime?), collective selfhood (who am I, and who are we?), and the meaning of events (what happened here--a coup, or a revolution?). Fossen argues that these questions constitute the heart of the question of legitimacy, but thus far have been neglected by theorists of legitimacy. Compelling and original, Facing Authority is a pragmatist alternative to predominant moralist and realist approaches to legitimacy in political philosophy.