The depth and breadth of a citizen’s political knowledge has long interested students of public opinion (Kreisberg 1949: 49; Luskin 1987: 856; Smith 1970: 668). On the question of depth, there is general agreement that the public is not only uninformed about current issues and events, but also misinformed (Delli Carpini and Keeter 1996; Kull, Ramsay, and Lewis 2003: 569). The signifi cant proportion of the American public (20 percent) that believes their president is a Muslim provides vivid, but representative evidence of the latter.