Sandra Day O'Connor is an American retired attorney and politician who served as the first female associate justice of the Supreme Court of the United States from 1981 to 2006. She was the first woman nominated and, subsequently, the first woman confirmed. Nominated by President Ronald Reagan, she was considered the swing vote for the Rehnquist Court and the first few months of the Roberts Court.
Prior to O'Connor's tenure on the Court, she was a judge and an elected official 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 Senate. On July 1, 2005, she announced her intention to retire effective upon the confirmation of a successor. Samuel Alito was nominated to take her seat in October 2005 and joined the Court on January 31, 2006.
O'Connor most frequently sided with the Court's conservative bloc. She often wrote concurring opinions that limited the reach of the majority holding. Her majority opinions in landmark cases include Grutter v. Bollinger and Hamdi v. Rumsfeld.