This chapter examines the structure of the most famous of the arguments, put forward by Thomas Hobbes and John Locke to see if either argument can provide a successful answer to the anarchists' challenge to the legitimacy of the state. The idea that political authority should be understood as consent-based has enjoyed enormous popularity in modern times and is the foundation of a kind of political justification for the state called a social contract argument. Modern readers of the Two Treatises generally find its political conclusions plausible. But that plausibility tends to blind them, to the highly implausible nature of Locke's social contract argument for those conclusions. Locke's argument concerns the relationship between his consent-based conception of political authority and the territory governed by that authority considers that, on Locke's view, a person's property is under the control of a political authority only through the fact of her consent to that authority.