This chapter evaluates some of the central tensions that characterize Jean-Jacques Rousseau’s egalitarian account of sovereignty. He formulates this account as the basis for a participatory ‘social contract’, meaning a voluntary form of association that aims to be both general enough to include the people as a whole, yet concentrated enough to command their government and to over-power the divisive influence of a wealthy elite. As he argued in his main political works, if it is sufficiently forceful, such a collective will can counteract the forms of inequality and servitude that have accompanied the historical rise of propertied and exploitative classes. Rousseau’s radical conception of mass power would soon inspire the most uncompromising sequences of the French Revolution. However, its emancipatory promise was also limited by its author’s sexism, his anachronism, and his failure to engage with some emerging forms of inequality and power, notably those associated with the rise of commerce, capitalism, and the transatlantic slave trade.