Justice Sandra Day O'Connor, the first woman appointed to the Supreme Court, announced Friday (July 1) that she is retiring, according to The Associated Press.

O'Connor, 75, is a moderate conservative who often lines up with the court's conservative bloc, but has been a key swing voter with her more liberal colleagues on issues such as abortion and the death penalty. The only female justice remaining is Ruth Bader Ginsburg.

O'Connor said that she expects to leave the court before the start of its next term in October, or whenever the U.S. Senate confirms her successor. Since it has been 11 years since the last opening on the bench, O'Connor's decision will give President Bush his first opportunity to appoint a new justice. There was no immediate word on who might be nominated as her replacement.

In a one-paragraph letter to Bush, O'Connor wrote: "This is to inform you of my decision to retire from my position as an associate justice of the Supreme Court of the United States, effective upon the nomination and confirmation of my successor," the AP reports.

Rumors of a Supreme Court vacancy have been swirling recently, but the speculation was mostly focused on Chief Justice William H. Rehnquist, 80, who is suffering from thyroid cancer. Neither before O'Connor's announcement nor in response to it has Rehnquist offered the public information on his plans.

The White House refused to comment on any possible nominees or whether Bush would appoint another woman to succeed O'Connor. However, possible replacements include Attorney General Alberto R. Gonzales and federal courts of appeal judges J. Michael Luttig, John G. Roberts, Samuel A. Alito, Jr., Michael W. McConnell, Emilio M. Garza and James Harvie Wilkinson III.

Other prospective candidates are former Solicitor General Theodore Olson, lawyer Miguel Estrada and former deputy attorney general Larry Thompson.

The only woman mentioned in legal circles is Edith Hollan Jones, a judge on the 5th U.S. Circuit Court of Appeals, who was considered for a Supreme Court seat by Bush's father.

Of course, there's always the possibility that the president will name a surprise candidate who is not well known to speculators.

O'Connor's appointment in 1981 by President Ronald Reagan ended a nearly 200-year run of an all-male Supreme Court.