It's almost an article of faith among Supreme Court watchers that President Obama will fill the bench's next vacancy—and perhaps the one after that, too— with a woman. The current court's sole female member, Ruth Bader Ginsburg, has said she is "lonely" there, and even if she's not the next to step aside and another women joins her, that's still just two out of nine. Americans seem quite certain that isn't enough. Former Justice Sandra Day O'Connor, on learning in 2005 that John Roberts would take her place, declared him"good in every way, except he's not a woman." Americans concur. In a CNN/USA Today/Gallup poll taken just before Roberts was appointed, 80 percent of respondents said it was a good idea to replace O'Connor with a woman, and 13 percent said it was "essential." And with women claiming a large share of responsibility for Obama's victory over John McCain, the demand for a more gender-balanced court is stronger than ever.
But why does Obama owe us another woman justice? Is it simply a matter of appearance? Is gender balance necessary for the court to have what political scientists like to call "social legitimacy"? Or is there something more fundamental that women bring to the bench—something about the way they decide cases—that makes the need for more of them so urgent?
Debate has raged for decades now about whether there is something unique about women's jurisprudence. A 1986 study of O'Connor's opinions published by professor Suzanna Sherry, now at Vanderbilt University, saw evidence there of a "feminine jurisprudence … quite unlike any other contemporary jurisprudence." Defenders of the notion of a woman's legal reasoning often build their case on the groundbreaking work of psychologist Carol Gilligan, whose 1982 book, In a Different Voice, claimed that female moral reasoning is fundamentally different. Men, the theory goes, prefer their law with rigid rules, clear lines, and neutral principles; women, meanwhile, want to look at the totality of the circumstances and apply broad discretion, preferring what Gilligan calls an "ethic of care" to an "ethic of rights."
So, for example, some of the different voice theorists would argue that O'Connor's preferences for flexible case-by-case standards in the context of abortion, or her concern for the uneasy nonbelievers in cases about public displays of religion, reflect a softer, more "relational" approach to the law, while Justice Antonin Scalia's emphasis on unchanging rules and crisp legal principles is, fundamentally, a guy thing. This is, of course, a rather broad-brush approach to both gender and judging, and some feminists object that it ultimately hurts women to talk of them in such gauzy generalities. Why perpetuate the idea that woman are all about tenderness and feelings while men are all about muscular rights?
Whichever side of the debate you espouse, the empirical studies on gender and judging have been almost completely equivocal so far. But in an award-winning 2008 paper titled "Untangling the Causal Effects of Sex on Judging," Washington University's Christina L. Boyd and Andrew D. Martin and Northwestern School of Law's Lee Epstein suggest that women judges really are different. Surveying sex discrimination suits resolved by panels of judges in federal circuit courts between 1995 and 2002, the researchers examined whether male and female judges decide cases differently, and went on to look at whether the presence of a female on a panel of judges affects the behavior of her male colleagues.
Here's what they found: The male judges were 10 percent more likely to rule against alleged sex-discrimination victims. And male judges were "significantly more likely" to rule in their favor if a woman judge served on their panel. Because Epstein, Boyd, and Martin were studying only sex-discrimination cases—situations in which gender is front and center—it's unclear whether their data would hold true in cases in which gender were beside the point. Still, an intriguing implication of this study is that male judges rule differently when they're sharing the bench with a woman. It may suggest female moral reasoning—if such a thing exists—might be contagious.
O'Connor, for her part, has been one of the most vocal detractors of the "different voice" theory of judging. She has been clear that "there is simply no empirical evidence that gender differences lead to discernible differences in rendering judgment." Somewhat paradoxically, however, O'Connor does believe that the personal experiences of diverse jurists influence the views of their colleagues. She has written, for instance, of the influence that Justice Thurgood Marshall had on her worldview. In her 2003 book, The Majesty of the Law, O'Connor described how Marshall, through his tremendous gifts as a "raconteur," pushed his fellow justices to re-evaluate their own moral truths; how his experiences with racial discrimination offered a window into that world for his white colleagues. It wasn't necessarily that Marshall wrote in a different voice. It was that he was able—as Linda Greenhouse, my former colleague at the Supreme Court, has argued—to show his colleagues that they did not always know what they thought they knew about race.
History proves that you can be the most empathetic, open-minded, and sensitive jurist in all the world—and still be a complete dolt about gender. It's why liberal lion William Brennan could write so expansively about equality and fairness and justice while still refusing to hire female law clerks. It's why Ginsburg was denied a clerkship with the legendary judge Learned Hand. (He refused to hire her because he liked to use salty language.) A wonderful new book by Fred Strebeigh called Equal: Women Reshape American Law, is full of stories about well-meaning men who thought they knew what women needed and the women who showed them they were wrong.
When it comes time for Obama to appoint a new justice, he'll have an embarrassment of female talent to choose from: To name just a very few, potential candidates include appeals court judges like Diane Wood, Sonia Sotomayor, Kim McLane Wardlaw; his new solicitor general, Elena Kagan; gifted academics such as Stanford Law School's Kathleen Sullivan and Pamela Karlan; Michigan Gov. Jennifer Granholm; and private attorneys like Teresa Wynn Roseborough. Each of these women has a different story and a different voice, and nobody believes for a moment that they all think alike. It took a few years of Ginsburg and O'Connor to show us that if there is any such thing as a women's jurisprudence, it differs radically from woman to woman.
Still, beneath all the formal legal reasoning at the Supreme Court, there are the countless stories of casual influence: the female law clerks, the secretaries, and the family members whose experiences, like Marshall's, slowly taught insulated justices how much they needed to learn. It's long past time for women to influence the high court in more direct ways. Women who want Obama to push for gender balance at the Supreme Court need to remind him that fighting for gender diversity at the high court isn't just for show. The real point may be to tell.
A version of this article appears in this week's issue of Newsweek.