Sandra Day O’Connor, the first woman on the United States Supreme Court, died on Friday in Phoenix at the age of 93. The Supreme Court announced her death in a statement, saying the cause was complications of dementia. In a public letter she released in October 2018, she announced that she had been diagnosed with the beginning stages of dementia, “probably Alzheimer’s disease,” and consequently was withdrawing from public life. President Ronald Reagan named her to the Supreme Court in 1981, fulfilling a campaign promise to appoint the first female justice. She served for 24 years, retiring in January 2006 to care for her ailing husband. The middle ground that she looked for tended to be the public’s preferred place as well, given the close attention she paid to current events and the public mood. Her moderate conservatism made her look in the end like a relative liberal. She lamented publicly that some of her majority opinions were being “dismantled.” Despite graduating near the top of her law school class, the notion that a woman might sit on the Supreme Court seemed distant indeed. Her route to success in arguing a case before her lay not in invoking legal doctrine or bright-line rules, but in marshaling the facts to demonstrate a decision’s potential impact.