Last month marked the 25th anniversary of Justice Thurgood Marshall's announcement that he was retiring from the Supreme Court after 24 years of service. We could use his wisdom in this badly fractured moment.

Many people within a decade or two of my age miss Marshall because of the way he voted. But that attitude, although common when we look at the court, masks something terribly cynical and even illiberal. The justice whom we love because he votes the right way isn't valued for who he is, but for the benefit we derive from him.

Let me offer a different perspective. I will admit, first, to a bias. I loved that old man. I served as one of his law clerks back in the early 1980s. After leaving the court in 1991, Marshall asked me to be the interviewer for his official oral history. He passed away before we could finish, but not before covering nearly all of his life before he joined the Supreme Court — the decades of litigating civil rights cases for little money, and often at risk to his life.

Marshall would tell us of presidents he had known and admired (particularly Harry Truman and Lyndon Johnson), and of segregationist politicians with whom he had negotiated. He talked about the pain of the ordinary black people he met in his work, and the perilous, hand-to-mouth existence of black civil rights lawyers back in the 1930s and 1940s. He told stories in order to teach. What he taught us was more than love of justice or tolerance of disagreement. He taught through example the importance of loving our neighbor across our differences.

Once I had occasion to ask him what he thought of John W. Davis, the distinguished New York attorney and former Democratic presidential nominee who argued the pro-segregation side in Briggs v. Elliott, one of the school cases decided by the Supreme Court in 1954 alongside Brown v. Board of Education. (Marshall represented the other side.)

Given that Davis was on the wrong side of the most divisive and important moral issue of the 20th century, I assumed that Marshall would respond to my prompt by heaping hellfire and damnation upon his head. But his answer surprised me.

"John W. Davis?" Marshall intoned. "A good man. A great man ... who just happened to believe in that segregation."

He wasn't being either ironic or sarcastic. He was sincere. Across the bitter divide of Jim Crow, Marshall had a remarkable ability to find the common humanity in his opponents. Again and again, he spoke highly of governors or members of Congress who were on the wrong side of the issue. He didn't care, Marshall used to say, what a man had to do to get elected. What he cared about was whether, when you shook hands on a deal, "his word was good."

The point is not that Marshall considered litigation or protests to be wrong. The point is that he was able, in the most tumultuous of times, to keep lines of communication open with those on the other side. Marshall's highest praise for others was this: "You could do business with him."

In our own sharply divided era, we've become all too accustomed to thinking of our opponents as either mendacious or malevolent. But we can learn from Marshall's example. He risked life and livelihood in a cause that inflamed far greater passions and fury than those over which we battle today. If we heed his example — if we look past our differences to embrace our common humanity — maybe we, too, can learn to do business again.

Stephen Carter is a Bloomberg View columnist and a law professor at Yale.