It's been a year of change for the U.S. Supreme Court, sparked by Sandra Day O'Connor's announcement in July that she was retiring. Nominated by former President Ronald Reagan, a Republican, in 1981, O'Connor served on the nation's highest Court for 24 terms. She was the Court's first female Justice.

O'Connor, 75, said that her age and desire to spend more time with her ailing husband are the reasons she is retiring. Her departure could influence a shift in the way future cases are decided. If the new Justice has very different views than O'Connor, the makeup of the Court will change. O'Connor often cast the deciding vote on the nation's most sensitive and serious issues.

President George W. Bush first nominated John Roberts to replace O'Connor. Following Chief Justice William Rehnquist's death in September, the President chose Roberts to fill that position. Roberts was later approved and is now the nation's Chief Justice.

O'Connor's seat is still in the process of being filled. Decisions made by the Supreme Court affect all Americans. With this in mind, the U.S. Senate is thoroughly interviewing the President's nominee, Judge Samuel Alito.

For being the first woman to serve on the Supreme Court and for triggering big changes in the nation's highest court, Sandra Day O'Connor is a nominee for TFK Person of the Year.