Sandra Day O'Connor, the first woman to sit on the Supreme Court and a crucial swing vote on divisive social issues such as abortion, will retire. She is 75 years old.

O'Connor, the court's 102nd justice, was nominated by Ronald Reagan in 1981 and quickly established herself as a judicial pragmatist. Although most of her votes have sided with the court's conservatives, she has no easily identifiable ideology.

Her centrist leanings have given her outsize influence on U.S. legal history due to her frequent role of casting the court's deciding vote.

O'Connor's position on abortion has been centrist. While raising numerous issues with its legal underpinning, she has never voted to overturn the 1973 Roe v. Wade decision recognizing a constitutional right to abortion.

She has also voted to defend affirmative action and, generally speaking, in favor of states rights and the rights law enforcement.

O'Connor's retirement leaves the first vacancy on the court in 11 years. The

Associated Press

said possible replacements include Attorney General Alberto R. Gonzales and appeals court judges J. Michael Luttig, John Roberts, Samuel A. Alito Jr., Michael McConnell, Emilio Garza and James Harvie Wilkinson III. The news service also named Solicitor General Theodore Olson, lawyer Miguel Estrada and former deputy attorney general Larry Thompson, and Edith Hollan Jones, a judge on the 5th U.S. Circuit Court of Appeals.