Washington ? A springtime rite that accompanies the cherry-blossom season is in full flower: speculation on which Supreme Court justices might retire, and when. The key players this time are Chief Justice William H. Rehnquist and Justices Sandra Day O’Connor and John Paul Stevens.

The end of the current court term is in sight, and on Monday the nine justices begin their last session of oral arguments. The court will continue meeting to issue decisions through June. In recent times, several justices have announced retirement plans fairly early in the spring.

Historically, justices have been inclined to give the White House and the Senate ample notice of retirement plans, except in circumstances where ill health has been a factor. That allows for a replacement to be selected before the start of the fall term in October.

None of the nine justices has said a word in public to indicate that this may be his or her last year on the court. Still, it seems every lawyer and law professor who studies the court has a theory.

The most common:

l Rehnquist, 77, has seen and done it all in 30 years on the court. He is ready to putter and paint.

l O’Connor, 72, similarly has accomplished what she hoped to do as the first woman named to the court. She has passed the 20-year benchmark and feels it is time to retire to Arizona, play golf and enjoy her grandchildren.

l Stevens will be 82 this month. While seemingly in good health, he may want to leave before anyone starts to whisper that he is not carrying his load.

The other six justices all are under 70 and are apparently healthy.

“It’s a great pastime for all of us, but really and truly nobody knows,” said John B. Attanasio, dean of the Dedman School of Law at Southern Methodist University.

That said, there are historical reasons to wonder whether a retirement might be imminent.

The current term is the court’s eighth with the same cast the longest such run since the 1820s.

Through the past 100 years, the average age for a Supreme Court retirement was 71, after serving 14 years on the bench. Rehnquist, Stevens and O’Connor have all passed both those benchmarks.

Justices historically have preferred to retire under the same party or philosophy that put them on the court.

Rehnquist or O’Connor, named to the court by Richard Nixon and Ronald Reagan, respectively, could leave secure that President Bush would seek to fill the seat with someone of similar conservative ideology.

Their decision, however, would be tempered by Democrats’ control over the Senate, which can confirm or deny the president’s judicial nominees.

If Republicans recapture control of the Senate in this fall’s elections, Bush would have a much freer hand in picking nominees. An anonymous source said the White House has privately lobbied Rehnquist and O’Connor to stay until after the elections.