John Locke affirms a right to revolt against tyranny, but he denies that a minority of citizens is at liberty to exercise it unless a majority of their fellow citizens concurs in their judgment that the government is a tyranny. In a recent article, Massimo Renzo takes an equivalent position, on which a revolutionary vanguard requires the consent of the domestic majority before being permitted to revolt. Against Locke and Renzo, I argue that a minority of citizens can have a liberty to revolt, whatever the domestic majority may hold. My argument concentrates on the moral force of majority rule, which turns out to presuppose the satisfaction of a number of background conditions. When any of these conditions fails to obtain, no domestic majority can justifiably block a minority’s liberty to revolt against tyranny. For the purposes of the theory of revolution, this minority has to be large enough to have a reasonable prospect of (military) success. Without that prospect, the minority will be anyhow forbidden to revolt, on grounds familiar from just war theory. However, for the purposes of the theory of political legitimacy, prospects of success are irrelevant. All that matters are the conditions under which any citizen is released from their ordinary duty not to overthrow the government.