Studies consistently establish that more experientially diverse decision-making bodies tend to avoid groupthink, consider different and more innovative approaches, and then reach better decisions. Given that every justice is already a lawyer, it makes sense to try to diversify across other educational, geographic and experiential axes. This was the case historically, as Harvard graduates shared the bench with former politicians, law professors and even autodidacts with no formal education.

Mr. Biden may want to look closely at another name reportedly on his short list: Judge J. Michelle Childs. She’s a product of the Columbia, S.C., public school system who earned a scholarship to the University of South Florida and got her law degree at the University of South Carolina—both public institutions. She made partner at a Columbia law firm practicing labor and employment law and has worked in state government and served as a state and federal trial judge. Both she and Judge Jackson are highly qualified to serve on the court, but in terms of sheer diversity, Judge Childs has an advantage.