Sandra Day O'Connor is a retired Associate Justice of the Supreme Court of the United States, having served from her appointment in 1981 by Ronald Reagan until 2006. She is the first woman to have served on the Court.
Prior to O'Connor's tenure on the Court, she was an elected official and judge 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.
Considered a federalist and a moderate Republican, O'Connor tended to approach each case narrowly without arguing for sweeping precedents. She most frequently sided with the Court's conservative bloc, although in the latter years of her tenure, she was regarded as having the swing opinion in many cases. 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.