Despite Barack Obama’s momentum in the early phase of the Democratic nomination, the process of selecting a nominee took longer than usual. Obama’s momentum, it seems, got stuck, and the 2008 Democratic presidential nomination was an unusually drawn out affair. Even when it appeared Barack Obama would win the nomination, many Clinton supporters said they would support John McCain in the general election. Why were some Democrats unwilling to join the Obama bandwagon once he emerged as a viable front-runner – and ultimately the Democratic nominee? In this paper we bring a unique set of panel data from the 2008 Cooperative Campaign Analysis Project (CCAP) to bear on questions about primary vote choice, examining the evolution of preferences over the unusually long and intense 2008 Democratic presidential nomination campaign. Attitudes about race predict vote choice in partisan contests; here we show that (conditional on the presence of a black candidate) these attitudes help explain the dynamics of candidate support over the prolonged intra-party contest for the 2008 Democratic presidential nomination.