Sandra Day O’Connor will be missed on the U.S. Supreme Court not only because of her moderate, compelling voice, her leadership on controversial issues ranging from affirmative action to church-state relations, and her trailblazing journey for women’s rights. She also will be missed most for her civility.

O’Connor, who announced Friday that she would resign as an associate justice after 24 years on the bench, has left a legacy of decision-making and clear, concise legal opinions that carried on the great traditions of the court. But it is her approach to the law and to public life that was so distinctive, and it will be a monumental challenge to replace – if those in charge of filling her seat want to replace it at all.

“There’s a civility that she brings to the process, a respect for the opinions of others and an ability to talk with people across the ideological divide that was a model of civic discourse. There’s very little of that left in public life,” said Kathleen Hall Jamieson, director of the Annenberg Public Policy Center at the University of Pennsylvania.

Jamieson has studied and written about civil discourse for years, but her opinion on O’Connor is based on more than academic research. Early last month, through Annenberg’s Student Voices project, Jamieson accompanied 50 high school students from Philadelphia and Cheltenham to Washington for a personal session with two Supreme Court justices.

The court’s nine members generally lead cloistered lives, as sequestered and controlled as royalty. Chief Justice William Rehnquist’s recent illness highlighted how little obligation the justices feel to communicate or interact with the public.

O’Connor shared that reluctance to disclose – she was notably reticent about the details of her bout with breast cancer – but unlike most of her colleagues, she relished the opportunity to reach out to the public, especially to schoolchildren. The most easily recognizable Supreme Court justice, she happily agreed to meet with the students, even in the midst of a grueling session of the court.

She and Justice Stephen Breyer left their robes in their chambers and spent an hour and a half with the students, in a conversation that the justices insisted not be scripted in advance. (An edited tape of the session will be available to schools in time for Constitution Day in September.)

“What most struck me when she was talking to the students was that she modeled civil discourse by being responsive, engaged, intelligent, thoughtful,” Jamieson recalls. “She didn’t patronize them. She treated them seriously, and with the respect that would encourage them to think that the Constitution was their document, too.”

That approach characterized her time on the high court, as she often tried to navigate the rough waters of partisan divide. O’Connor wasn’t wishy-washy in her opinions, but her loyalty to the law superseded her devotion to ideology, and she didn’t skewer the first to serve the second.

When asked by a student whether she would vote for a decision that was constitutional even if it violated her own moral values, O’Connor answered: “It doesn’t matter what I personally think or would do at all. It matters that the Constitution provides the laws of the United States, and we do our best to interpret those faithfully.”

O’Connor’s civility extended to the way she treated others – she’s famous for being kind to her law clerks (far from usual) and for, literally, carrying her own bags. She was raised on a hardworking Southwestern cattle farm and forced to establish herself as a lawyer in an atmosphere hostile to women, which taught her self-reliance. It also could have left her bitter.

Instead, it left her superbly equipped to solve problems and open doors. It taught her what her more strident and self-righteous colleagues miss: that power resides in those who can craft the best solutions by listening carefully, arguing well, and retaining the respect of all. The great power that O’Connor wielded was not the power of the loudest voice or the sharpest tongue. Hers was the power of the open mind.

I hope the president values that legacy – and that her successors follow it.