According to public reason liberalism, the laws and institutions of society must be in some sense justifiable to all reasonable citizens. But why care about justifiability to reasonable citizens? Recently, Gerald Gaus has developed a novel and sophisticated defence of public justification. Gaus argues that our everyday reactive attitudes of resentment and indignation presuppose public justification and that these reactive attitudes are essential to social life. In this article, I challenge the first premise by considering cases in which agents are (...) liable to the reactive attitudes for violating moral rules that they had no sufficient reason to endorse, and I challenge the second premise by drawing on recent work on moral responsibility that suggests that social life would still be possible, and perhaps even improved, in the absence of the reactive attitudes. Finally, I question whether the reactive attitudes are even the kind of thing that could justify public reason. (shrink)