Let’s be clear. Sandra Day O’Connor is no Ruth Bader Ginsburg. Ginsburg gave us the legal architecture of women’s place in America. O’Connor, the first woman on the U.S. Supreme Court, gave us George W. Bush. The tie-breaker in Bush v. Gore, O’Connor added color and contrast to the court, but the Reagan appointee was vastly more Republican than feminist. And while the ostensible thesis of the book is that sisterhood is powerful, the main story that author Linda Hirshman tells us is the story of “The Notorious RBG.”

This is not a standard biography or dual biography, nor has Hirshman interviewed the principals. The book is based on the author’s own legal expertise and experiences practicing before the Supreme Court, her access to various justices’ papers and opinions, as well as interviews with supporting cast. Smart money says that O’Connor declined to participate and the book’s concept would not work with Ginsburg interviews alone. Still, without a direct word from her subjects, the writer seamlessly weaves their voices, along with history, politics and her own point of view, which only the sleepiest reader could miss.

Hirshman, whose prior books include “Victory: The Triumphant Gay Revolution,” is a deliciously sly writer. “Harvard noticed that they didn’t have any women professors.” Or “[O'Connor's'] passionate advocacy for Rehnquist’s confirmation for a seat she, as an Arizona state senator, had proposed for a woman, neatly presents the question of how serious a feminist she was.” Meantime, Ginsburg, a crafty strategist herself, began developing a civil rights movement based on sex, even as some feminist scholars and sometimes the ACLU, where she headed the Women’s Rights Project, disagreed with her. She built case law with facts that appeared counter-intuitive—representing male plaintiffs claiming discrimination—building on one ‘gotcha’ moment after another. If a widowed father was denied his wife’s Social Security benefits, though a wife was entitled to her deceased husband’s, well, then, the discrimination was based on sex.” Next case.

Alix Kates Shulman’s, “A Marriage Agreement,” a 1970 radical domestic equality contract that divided all home and child-related work between Shulman, the women’s liberation activist, and her husband, had sparked a fire in Ginsburg, the young professor of federal procedure. As lawyer and judge her long-range vision and strategy to establish equality regardless of gender, has been to end sex role stereotypes and discrimination through the equal protection clause. At the same time, the Equal Rights Amendment—which O’Connor, as legislator, had not considered necessary—might have avoided challenging one statute at a time. (It fell but three states short of enactment.)

Ginsburg’s fight has long been “to transform the constitutional status of women in America.” It should not surprise us, though it does, that the fiercely pro-choice Ginsburg has always disagreed with the Court’s 1973 Roe v. Wade analysis. That result is based on privacy, physicians’ expertise, trimesters of pregnancy, while Ginsburg argues that a woman’s right and access to abortion should have been established on equal protection grounds, as developed in an amicus brief by New York lawyer, Nancy Stearns.

For Ginsburg, the “justification for protecting abortion rights is women’s equality.” In her robust vision of women’s lives, Hirshman writes, “it is the unfettered right to make the decision that is central to a woman’s equality. Telling her what to do is the core violation.” No one has ever said it better than Ginsberg: “Women need to control their reproduction if they are going to participate as equals in American life.”

The appointment of a woman to the Supreme Court bench albeit from the extremely small pool that was available at the time, meant that this branch of government would no longer belong to men only. O’Connor’s appointment thrilled millions of women, some supporting the particular woman who had arrived, but most realizing that it was a huge game-changer. A woman could be, would be a justice of the Supreme Court of the United States. Never mind that on the critical-to-women-issues of reproductive rights, O’Connor had called abortion, “abhorrent,” “repugnant,” and inconsistent with the interests of the fetus (even before “personhood” came along). Yet, as Hirshman tells it, while O’Connor would not “send women back to 1972 [pre-Roe] … she would not let them move beyond the backlash that erupted after 1973 either.”

Still, the writer considers the first two women justices more effective together than separate even as she writes that O’Connor, who was never a feminist and distanced herself from feminism, was not a committed strategist for women’s rights and calls much of her work “ungenerous, even in cases where she voted for the woman’s side….”

Yet according to Hirshman when Ruth joined the court, the first woman there, O’Connor, was more likely to vote on the liberal side in cases involving women’s issues than in any other area. O’Connor recognized Ginsburg’s place in feminist jurisprudence. When discrimination at the all male Virginia Military Institute was challenged, the votes were there to order desegregation. The protocol of how opinions are assigned meant this one would have gone to O’Connor. But she had the grace and wisdom to defer to her sister in law who had earned the right to author this opinion. “This is Ruth’s,” she announced to the assembled justices.

O’Conner also recognized that she herself was an affirmative action baby. “How do you think I got here?” she asked her exclusionary bretheren. But, Hirshman writes, she “tightened the noose” around that means of opening doors, until she cast one saving vote just before her retirement.

O’Connor was not a voice for social change, but her very being at a certain time and place in America was in itself, social change.

But real social change can come from empathy. Even in the Supreme Court that confronts issues of law (though not infrequently politics), that elusive quality of empathy, feeling what another has experienced, can be the most telling characteristic. Neither race nor gender is a predictor of empathy.

But Ginsburg, considering the laughter of her male colleagues who did not understand the devastating impact of a strip search on Savannah Redding, an adolescent schoolgirl accused of storing a Tylenol tablet in her underwear, explained it simply: “They’ve never been a 13-year-old girl.”

O’Connor was no longer on the bench when Redding v Safford School District reached the court, so we can only speculate on how she would have voted. But this much we know: the first woman on the Supreme Court, like the second, was once a 13-year-old girl. Linda Hirshman’s point, exactly. And now the sisters in law are three.