Sandra Day O'Connor (March 26, 1930 – December 1, 2023) was an American attorney, politician, and jurist who served as an associate justice of the Supreme Court of the United States from 1981 to 2006. Nominated by President Ronald Reagan, O'Connor was the first woman to serve as a U.S. Supreme Court justice. A moderate conservative, she was considered a swing vote. Before O'Connor's tenure on the Court, she was an Arizona state judge and earlier an elected legislator in Arizona, serving as the first female majority leader of a state senate as the Republican leader in the Arizona Senate. Upon her nomination to the Court, O'Connor was confirmed unanimously by the United States Senate.
O'Connor usually sided with the Court's conservative bloc but on occasion sided with the Court's liberal members. She often wrote concurring opinions that sought to limit the reach of the majority holding. Her majority opinions in landmark cases include Grutter v. Bollinger and Hamdi v. Rumsfeld. In 2000, she wrote in part the per curiam majority opinion in Bush v. Gore and in 1992 was one of three co-authors of the lead opinion in Planned Parenthood v.