Local elections in the past four decades have provided valuable data for political scientists to test various hypotheses concerning racial relations in the United States. Past research has shown, for example, that the elections of African American candidates to powerful offices in urban America are closely related to the changing racial demographics of cities (Browning, Marshall, and Tabb 2003). More specifically, racial polarization in a city's mayoral election tends to be at a maximum when whites and blacks each compose about 50% of the city's population. On the other hand, a biracial coalition between whites and blacks led by a charismatic black candidate is more likely to win elections when blacks become a clear majority of the city population (Liu and Vanderleeuw 2007). One remaining question that has increasingly drawn attention from scholars is the condition under which a multiracial coalition may be successfully formed.