The more white voters support a policy, the more likely it is to be enacted. The more black voters support a policy, the less likely it is to be achieved.
The story is similar for several other groups. The more that women, the poor, or Hispanics support a federal policy, the less likely the policy is to be enacted. Strikingly, as women move from universal opposition to a proposal to universal support, its odds of adoption plummet from 75 percent to 10 percent.
Source: The False Promise of Black Political Representation – The Atlantic