AMNA NAWAZ: Sandra Day O'Connor, the history-making justice who was the first woman to serve on the U.S. Supreme Court, died this morning in Phoenix from complications of dementia and a respiratory illness.

Chief Justice John Roberts said today that when O'Connor joined the court in 1981, she met the challenge -- quote - - "with undaunted determination, indisputable ability, and engaging candor."

Judy Woodruff has this remembrance.

SANDRA DAY O'CONNOR, Former Supreme Court Justice: I wanted, since I was the first, not to be the last.

And I wanted to do the job well, so it would provide encouragement for women to serve in the future.

JUDY WOODRUFF: Sandra Day O'Connor broke the gender barrier at the U.S. Supreme Court, and ultimately became a critical vote on abortion rights, affirmative action and even the election of a president.

It was a long journey from the family cattle ranch in Southeastern Arizona.

She recalled those early years in a "NewsHour" interview in 2002.

SANDRA DAY O'CONNOR: It gives a person a little confidence, a bit of self-reliance, because you know you have to solve the problems yourself.

You can't always turn to other people to do them, a belief in independence.

JUDY WOODRUFF: The young Sandra Day earned degrees at Stanford University and its law school, where she was a classmate of future Chief Justice William Rehnquist.

She married another law grad, John O'Connor, and tried for a job practicing law.

But it was the 1950s, and more than 40 firms turned her down.

Eventually, after having children, she turned to politics, serving in the state Senate, and became a judge for Arizona's State Court of Appeals.

Then, in 1981, President Ronald Reagan nominated O'Connor to the U.S. Supreme Court.

MAN: The truth, the whole truth, and nothing but the truth, so help you God.

SANDRA DAY O'CONNOR: I do so swear.

JUDY WOODRUFF: She described herself as a judicial conservative and won unanimous Senate confirmation.

But after joining the court, she came to be regarded as more moderate and a swing vote.

SANDRA DAY O'CONNOR: Some of the decisions are made by drawing very fine lines.

And reasonable people can disagree on where those lines should be drawn.

I have been there.

And I know how challenging it is.

It is not surprising at all that some cases are decided by drawing fine lines with five people here and four people on the other side.

JUDY WOODRUFF: In 1992, Justice O'Connor was the critical fifth vote against overturning the landmark Roe v. Wade decision that legalized abortion.

Later, she joined a one-vote majority in striking down state limits on so-called partial-birth abortions.

In 2003, she wrote the majority opinion upholding the use of race in deciding college admissions.

And she voted with the 5-to-4 majority in Bush v. Gore, the case that ultimately settled the bitterly disputed 2000 presidential election.

In later years, O'Connor acknowledged criticism that she lacked a clear judicial philosophy, but she defended her case-by-case approach.

SANDRA DAY O'CONNOR: You have to answer the question, like it or not.

And the questions deserve a valid legal response, even if the response isn't one that will be easily understood.

You have an obligation as a member of the court to do what you are bound to do under federal law, even if it isn't an attractive resolution from a public standpoint.

JUDY WOODRUFF: She was the lone woman on the High Court for 12 years, until President Bill Clinton nominated Ruth Bader Ginsburg in 1993.

O'Connor retired from the court in 2006, citing her husband's health, but continued hearing cases in the U.S. Courts of Appeals.

And she made time to visit schools, actively promoting the importance of civics education.

SANDRA DAY O'CONNOR: I wanted to teach young people in America how they can be part of the governmental structure and help decide what problems to tackle and how to solve them.

JUDY WOODRUFF: The retired justice devoted much of her attention to caring for her husband, John, who suffered from Alzheimer's and died in 2009.

That same year, O'Connor was awarded the Presidential Medal of Freedom, the nation's highest civilian honor.

At the ceremony, President Obama said she forged a new trail and built a bridge behind her for all young women to follow.

O'Connor reflected on it all in an interview with the "NewsHour" in 2009.

SANDRA DAY O'CONNOR: I was asked in my Senate confirmation hearing about how I'd like to be remembered.

I called it the tombstone question.

And I said, I hope the tombstone might read, "Here lies a good judge."

JUDY WOODRUFF: At the age of 88, the retired justice announced she had formally withdrawn from public life.

She wrote to the High Court that she had beginning stages of dementia, probably Alzheimer's.

Sandra Day O'Connor lived out her final years in Arizona.

AMNA NAWAZ: Sandra Day O'Connor was 93-years-old.

John Yang picks up our coverage of her legacy both on and off the Supreme Court.

JOHN YANG: O'Connor's tenure on the Supreme Court is notable not just because she was the first woman, but also because of what she did in her 24 years there.

Joan Biskupic is the CNN Supreme Court analyst and author of "Sandra Day O'Connor: How the First Woman on the Supreme Court Became Its Most Influential Justice."

Joan, along those lines, you write in the book that her appointment didn't just change the court; it transformed the court.

What do you mean by that?

JOAN BISKUPIC, Author, "Sandra Day O'Connor: How the First Woman on the Supreme Court Became Its Most Influential Justice": It really did, John.

And it's great to be with you, even though at this moment we really feel some sadness, along with the weight of history, for how influential Sandra Day O'Connor was.

I like to say that she made history certainly by being the first woman justice on the Supreme Court, but, also, she was a real politician on the court.

She came knowing how to count votes, knowing how to work consensus.

And she had a very pragmatic style that involved not just trying to find the center of the law in America, but also trying to find the center of the court.

So there was no one like her before 1981, and there will be no one like her going forward.

She influenced so many important areas that I -- that you all just touched on, abortion rights, religion, racial affirmative action.

But her overall approach was to ensure that, when those nine justices got together in the conference room with nobody else but them, that everyone walked away feeling like they got something.

Now, people were critical of that sort of consensus-building, center-of-the-court approach she had, but it really did steady the law in America in a way that we don't have right now.

JOHN YANG: You mentioned her political skills, she was Senate majority leader in the Arizona Senate, and also her stand on abortion.

Now, when she voted to preserve Roe v. Wade last time it was challenged, it wasn't just her vote that was important.

Is that right?

JOAN BISKUPIC: That's right.

She brought together a coalition.

It was her and fellow Justices David Souter and Anthony Kennedy, both of whom were Republican appointees also, and got everyone together to preserve the 1973 landmark Roe v. Wade, which, of course, was overturned in last year's decision by this Supreme Court.

And you referred to the 1992 decision in Planned Parenthood v. Casey.

She wrote something very compelling at the time.

She acknowledged that many people might not have wanted what the court did in Roe v. Wade in 1973, and she might not even have wanted it in 1973, but she wrote about how all of America had come to live with it.

And she said it wasn't the court's role to impose its own morality or sense of social norms on the country, not to impose somebody's personal morality on the country, but to sort of take account of the entire population and how much that precedent had been around for, at that time, from 1973 to 1992, 20 years.

And then it wasn't until 2022 that the court completely overturned it, obliterating nearly a half-century of precedent.

JOHN YANG: And another area where she was influential was supporting or upholding race-based college admissions, which also was overturned last year.

What did she say about when her opinions were overturned after she left the court when she was asked about how she felt seeing some of her opinions overturned?

JOAN BISKUPIC: Well, John, I talked to her in about 2009 at a legal conference.

And, at that point, not everything had been reversed.

The court, with her successor, Samuel Alito, had already started rolling back some of her decisions, but not the big-ticket ones we have just referred to.

And she used the word dismantling.

And she expressed frustration that her decisions were being dismantled.

But little did she know what was to come.

JOHN YANG: On a personal note, Joan, you write that she was very eager for the justices to build relationships away from the court, outside the courtroom, outside the conference.

What sorts of things did she do?

JOAN BISKUPIC: Oh, she was always arranging things.

If it wasn't a bridge party, it was a trip to see some musical event.

If it wasn't that, she just -- she was -- it's funny.

She was an only child for about 12 years of her life.

She had two younger siblings, but she was the kind of person who I think her instinct after her somewhat lonely life on the ranch, her Lazy B Ranch in Arizona, made her always want to have people around.

But she was -- I refer to her politician's touch in trying to bring people around her, and because I think she realized, John, that to have smooth relations inside the court, you needed to build relationships outside the court with your colleagues.

So she was always doing dinners.

She was known for trying to arrange potlucks, bringing things in for her law clerks and also trying to enlist her fellow justices for various events.

And she was the one, John, who started the practice that they have now of having lunch together on days that they hold oral arguments.

And I remember Justice Clarence Thomas saying to me that she would -- she would say: "You have to come eat with us.

You have to."

And she was doing that with all of them.

David Souter, one of her shyer colleagues, resisted a bit.

But she ensured that all nine of them would have lunch together after oral arguments.

And I think that built a lot of really good will among the justices during her tenure.

JOHN YANG: Supreme Court analyst Joan Biskupic on Sandra Day O'Connor, thank you very much.

JOAN BISKUPIC: Thank you, John.