On Friday, March 21st 2014, Russia unilaterally annexed the Crimean peninsula, part of the sovereign state of Ukraine. Does Russia have legitimate authority over the people of Crimea? To address this question, and the more general issues it illustrates, I consider what competing accounts of legitimate political authority imply in cases of unilateral annexation, and illustratively apply them to the case of Crimea. I develop and defend what I call a “political-justice view” of legitimate authority, according to which authority is legitimate if its exercise is conducive to justice, understood politically. When justice is understood politically, existing institutions—provided they meet some minimal moral standards—are partly constitutive of its demands. I argue that, on this view, Russia’s de facto authority over Crimea is illegitimate, but for reasons different from those typically cited in media discussions, and in the political-theory literature on territorial rights.