Abstract:  It appears that one of the aims of John Rawls’ ideal of public reason is to provide people with good reason for exercising restraint on their nonpublic reasons when they are acting in the public political arena. I will argue, however, that in certain cases Rawls’ ideal of public reason is unable to provide a person with good reason for exercising such restraint, even if the person is already committed to Rawls’ ideal of public reason. Because it is plausible to believe that such cases are widespread, the issue I am raising represents a serious problem for Rawls’ account of public reason. After posing this problem, I consider potential responses on behalf of Rawls’ view, and I reply to those responses. The moral of this story, as I see it, is that the kind of duty an ideal of public reason aims to place on citizens must be more modest than Rawls supposes.