WASHINGTON — The first woman to serve on the nation’s highest court is dead at 93.

Sandra Day O’Connor, a groundbreaking justice on the U.S. Supreme Court, died Friday in Phoenix, Arizona of complications related to advanced dementia, probably Alzheimer’s, and a respiratory illness, according to an announcement from the court.

President Ronald Reagan nominated O’Connor in 1981, and she was confirmed by the full Senate, 99-0, in September of that year.

The moderate O’Connor, who served on the bench until her retirement in 2006, was often the decisive vote in major cases that reached the Supreme Court in her nearly quarter-century as associate justice.

The justices issued rulings in high-profile cases during O’Connor’s tenure, including Bush v. Gore, which settled the 2000 presidential contest in George W. Bush’s favor, and Planned Parenthood of Southeastern Pennsylvania v. Casey, a 5-4 decision that affirmed the constitutional right to an abortion but with leeway for states to impose some restrictions. O’Connor sided with the majority in both cases.

“She was consequential,” journalist and historian Evan Thomas told the National Archives in 2019 while promoting his biography “First: Sandra Day O’Connor.”

She cast the so-called “swing vote” 330 times in 24 years, Thomas said.

“And where it really mattered was in abortion rights and affirmative action,” he said, referring to several cases, including Grutter v. Bullinger, which upheld the consideration of race in the University of Michigan’s law school admissions.

In 2022, O’Connor’s successor, Justice Samuel Alito, wrote the majority opinion overturning Planned Parenthood v. Casey and Roe v. Wade, striking down abortion rights at the federal level.

A ‘true public servant’ and ‘trailblazer’

Chief Justice John Roberts said in a statement Friday that O’Connor “blazed an historic trail as our Nation’s first female Justice.”

“She met that challenge with undaunted determination, indisputable ability, and engaging candor. We at the Supreme Court mourn the loss of a beloved colleague, a fiercely independent defender of the rule of law, and an eloquent advocate for civics education. And we celebrate her enduring legacy as a true public servant and patriot,” he said.

Senate Minority Leader Mitch McConnell of Kentucky said in a statement that the “nation mourns the passing of a towering figure in the history of American law.”

“… From her election as the first female Majority Leader in the history of American legislatures to her confirmation as the first female Justice of the U.S. Supreme Court, Sandra Day O’Connor led with a brilliance and conviction that disarmed resistance. Her vote on the court frequently determined the majority in landmark cases, and the legacy of her role in landmark decisions reviving federalism during her first several terms on the Court continues to resound in Constitutional jurisprudence,” McConnell said.

In the mid-1990s and 2000, O’Connor provided decisive votes in two 5-4 decisions that found federal laws unconstitutional under the Commerce Clause, including sections of the Violence Against Women Act and a federal law that criminalized carrying a firearm within 1,000 feet of schools.

Senate Majority Leader Chuck Schumer of New York said O’Connor was the “conscience of the Court.”

Schumer said in a statement issued Friday that O’Connor “was one of the true historic figures of the 20^th century. In decision after decision, Sandra Day O’Connor was often the key vote in defending the rights of Americans—in protecting clean air, in protecting women’s rights, in protecting against discrimination, in protecting voting rights. I join Americans all across the country in mourning her passing today.”

Speaker of the House Mike Johnson of Louisiana described O’Connor as a “trailblazer” and “legal giant” in a Friday morning post on X.

“As the first woman to ever serve on the Supreme Court, Justice O’Connor inspired a generation of women — including the five female Justices that succeeded her — to chart a path that previously seemed unattainable,” he said.

“Despite never serving as Chief Justice, she was widely regarded as the most powerful Justice on the bench during her tenure.”

The women who followed O’Connor’s appointment to the court included Ruth Bader Ginsburg, nominated by former President Bill Clinton in 1993; Sonia Sotomayor and Elena Kagan in 2009 and 2010, both nominated by former President Barack Obama; Amy Coney Barrett, nominated by former President Donald Trump in 2020; and Ketanji Brown Jackson, nominated by President Joe Biden in 2022.

Obama released a statement Friday recounting the well-known story of O’Connor’s challenges finding a job in the legal field as a woman in the 1950s, when she was asked about her typing skills and offered work as a legal secretary.

“Fortunately for us, she set her sights a little higher – becoming the first woman to serve as a U.S. Supreme Court justice,” Obama said. “As a judge and Arizona legislator, a cancer survivor and child of the Texas plains, Sandra Day O’Connor was like the pilgrim in the poem she sometimes quoted – forging a new path and building a bridge behind her for all young women to follow. Michelle and I send our thoughts to Sandra’s family and everyone who learned from and admired her.”

From the Southwest to the nation’s capital

O’Connor was born on March 26, 1930 in El Paso, Texas, and grew up on a ranch in Arizona.

She graduated near the top of her law school class at Stanford University in 1952.

O’Connor began her law career as deputy county attorney of San Mateo County, California, followed by a position as a civilian attorney for Quartermaster Market Center, Frankfurt, Germany from 1954 to 1957.

O’Connor practiced law in Maryvale, Arizona until 1960 and went on to serve as assistant attorney general of Arizona from 1965 to 1969.

She followed her time in the attorney general’s office with multiple terms in the Arizona state Senate beginning in 1969 and eventually serving as the body’s majority leader.

In 1975, she was elected as a Maricopa County Superior Court judge and served until 1979, when she was appointed to the Arizona Court of Appeals.

Maricopa County Recorder Stephen Richer, a Republican, released a statement Friday saying O’Connor “represented the best of Arizona and our entire country.”

Phoenix Mayor Kate Gallego described O’Connor as “a pioneer from day one – a young, self-sufficient daughter of ranchers who blazed a trail to serve in the highest court in the country.”

“She shattered glass ceilings at every turn in her life, from pursuing a law degree at Stanford during a time when many schools did not accept women, to challenging workforce barriers, to being an active working mom. She was an inspiration to me and to so many other Arizonans,” said Gallego, a Democrat.

A crucial figure for women in law

O’Connor authored five books, including her 2001 memoir “Lazy B” about her childhood and adolescence on a cattle ranch, and 2013’s “Out of Order: Stories from the History of the Supreme Court.”

O’Connor remained on the high court’s bench after being diagnosed with breast cancer in 1988 and undergoing surgery and cancer treatment.

O’Connor is often credited as a crucial player in opening the legal field for more women.

Former House Speaker Nancy Pelosi of California said in a statement Friday that O’Connor was “an icon for working mothers and an inspiration to women across the country and around the world.”

“Beyond shattering a glass ceiling, her service on the bench reflected our nation’s highest ideals: courage, integrity, patriotism and justice.? At the same time, she was insistent on not being the last – mentoring so many women in law, including our beloved Ruth Bader Ginsburg,” Pelosi said.

Jessie Kratz, editor of the National Archives blog, wrote in 2018 that when O’Connor was appointed to the Supreme Court, only 36% of law school students were women. That figure rose to 48% by O’Connor’s retirement in 2006.

O’Connor is survived by three children, six grandchildren, and her brother Alan, whom she worked with as a co-author, according to the court’s Friday announcement.

Her husband, John O’Connor, with whom she shared a storied romance recounted by many journalists, died in 2009.

Funeral arrangements for O’Connor had not yet been released by the court as of Friday morning.

The Arizona Mirror’s Caitlin Sievers contributed to this report.