People in each minority group will also care about issues outside their group. Gun owners care about safety net levels. Gay people care about the environment. F

People in each minority group will also care about issues outside their group. Gun owners care about safety net levels. Gay people care about the environment. Family-values types care about crime. So people won't use all their credits or dollars for single issues. That is the logic of the quadratic function; marginal votes even for something you care a lot about will be too expensive unless used for something else.