Justice Sandra Day O'Connor, the first woman on the U.S. Supreme Court and a moderate conservative who often cast the key decisive vote, announced her retirement on Friday, setting the stage for a major political battle over her successor. "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," O'Connor, 75, said in a letter to President George W. Bush, according to Reuters. --SP 1906 Local Time 1606 GMT
