This thesis examines consent as the purported criterion of legitimate political authority and basis of political obligation in modern liberal democracies. Liberal consent theory posits autonomy as the basis of legitimate political authority, in as much as consent is an act of the individual's free, autonomous will. Voluntary subjection to political power transforms it into genuine political authority. On this view, consent is the mechanism by which autonomy is protected in social interactions generally, including those of a political nature. Only those political relationships that are based on genuine, autonomy-protecting consent are legitimate: only they can give rise to legitimate political authority over others and only they can give rise to real obligations to obey any rule set over us by another.