A growing body of work has examined the psychological underpinnings of conspiracy theory endorsement, arguing that the propensity to believe in conspiracy theories and political rumors is a function of underlying predispositions and motivated reasoning. We show, like others, that rumor endorsement can also be a function of individuals' group attitudes. In particular, among white Americans, birther beliefs are uniquely associated with racial animus. We merge this finding with other work which shows that rumors are more strongly endorsed by the individuals most motivated and capable of integrating them among their pre-existing attitudes and beliefs. We find, therefore, that it is white Republicans who are both racially conservative and highly knowledgeable who possess the most skepticism about Obama's birthplace.