At both levels, I found that blacks hold much less sway than whites. For example, a federal policy with no white support has only a 10 percent chance of being enacted, while one with universal white support has a 60 percent shot of adoption. But while a proposal with no black support has a 40 percent chance of becoming law, one enjoying unanimous approval has only a 30 percent probability of enactment. In other words, as support for a policy rises within the black community, the odds of it being achieved actually decline.

Likewise, whether most black voters are conservative or liberal, state legislative outcomes barely budge. But vary the views of white voters to an equivalent degree, and a state’s policies go from looking like Alabama’s to resembling Michigan’s, even controlling for black and white population size.

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. Changes in the ideology of female or poor voters also have no effect on state legislative outcomes (although shifts in the views of Hispanic voters do). In contrast, both federal and state laws are acutely sensitive to the preferences of whites, men, and the rich.

These results help explain the rage that has recently coursed through America’s cities. If blacks seem not to be satisfied with (mostly) uninhibited access to the polls and (close to) proportional representation, this is because they should not be content with these achievements. What really matters in a democracy is getting policies enacted that correspond to people’s views. And on this front, blacks still have a long way to go. Their opinions—on vital issues like crime, welfare, and housing—are too often ignored by elected officials when they conflict with whites’ preferences. This grim reality is well worth getting upset about.

More broadly, the results also highlight other distortions of the political process. Unsurprisingly, in this era of skyrocketing inequality and campaign-finance deregulation, policymakers pay closer attention to the views of the rich than to those of the poor (or of the middle class). More unexpectedly, women are largely ineffectual politically despite their large numbers, high turnout rates, and substantial representation. None of these assets provides them with what a healthy democracy should: laws as reflective of their preferences as of those of men. And Hispanics seem to hold an intermediate position, neither as weak as blacks nor as influential as whites.

So how might the promise of American pluralism be fulfilled—so that public policy is about equally responsive to each group’s views? Unfortunately, this is where we reach the limits of current academic knowledge. We can now quantify the power wielded by different groups. But neither my work, nor anyone else’s, has determined what the causes of group influence might be, let alone how disparities in clout can be corrected.