But seldom do these courts look anything like an increasingly diverse America.

We found that nearly half of all states do not have a single justice sitting on their high courts who is black, Asian, Latino, or Native American — even though people of color make up about 40 percent of the population. In eight of the 24 states with all-white high courts, people of color make up at least a quarter of the population. Thirteen states have not seated a single justice of color since at least 1960. Eighteen states have never seated a black justice.

The dearth of gender diversity is also appalling. Women hold only 36 percent of the seats on top state courts. Seventeen states have only one female justice. (State supreme court benches have five to nine justices.)

We also found that not only are state high court judges overwhelmingly homogeneous, but also, by some measures, state courts are becoming less reflective of the nation’s diversity than they were a generation ago. While there are more lawyers of color than ever before , we found that the gap between the proportion of people of color on the bench and their representation in the American population was higher in 2017 than it was in 1996.

The public legitimacy of our entire judicial system is under threat if the judges making crucial decisions about the law don’t reflect the diversity of the communities affected. As former Justice Yvette McGee Brown of the Ohio Supreme Court observed, the public’s perception of justice suffers “when the only people of color in a courthouse are in handcuffs.”

What’s more, research has shown that diversity on the bench enriches judicial deliberations. Studies of federal courts found that when a female justice or a justice of color sits on a panel, their male or white colleagues are more likely to side with plaintiffs in civil rights cases.