Updated

Looking frail, his voice clear but slightly hoarse, Chief Justice William H. Rehnquist (search) returned to the bench Monday for the first time since being diagnosed with thyroid cancer (search) last October.

Rehnquist, 80, joined his eight fellow justices in emerging from behind a curtain, as is the customary practice, to open the court's latest two-week series of arguments. He then swore in new members to the Supreme Court Bar (search).

No mention was made of his illness and none of the other justices said anything to him before the start of the first argument, a case from Colorado in which a woman was seeking to sue her local police department for its failure to prevent her estranged husband from killing her three daughters.

Rehnquist asked several questions during the two hours of arguments, at one point suggesting it is unrealistic to impose new legal obligations on already-overworked police departments in handling domestic violence complaints.

He took one break, leaving his chair for a few minutes during the first argument, as has been Rehnquist's custom in previous arguments, to stretch his back. At the conclusion he struggled momentarily to get out of his chair. Justice John Paul Stevens (search), who at 84 is the court's oldest member, assisted Rehnquist to a nearby railing.

Few details of Rehnquist's illness have been disclosed. However, medical experts have said that the treatment plan — chemotherapy and radiation — indicated he might have the most serious type of thyroid, meaning there was a distinct possibility he would never be able to return to the bench.

Dr. Michael Weiss, a throat cancer specialist at the Maimonides Medical Center in New York, warned against reading too much into Rehnquist's return.

"Certainly it's a good sign," he said. "The fact that he's back to work and moving under his own strength and not totally enfeebled seems to suggest he might do all right for a while."

Rehnquist last sat for arguments Oct. 13. He has been seen in public only one time since announcing on Oct. 25 that he has cancer and undergoing a tracheotomy to help him breathe.

He has been working regularly at the court for many weeks, presiding over private meetings of the justices, reading transcripts of the arguments and voting on decisions, but not appearing for arguments.

Rehnquist's only public appearance was in January, when he swore in President Bush for a second term. He walked with a cane and his voice sounded weak, but he was able to perform his duties.

Rehnquist presided last week over a two-hour, closed-door meeting of the Judicial Conference of the United States, the policy-making body of the federal judiciary. Attendees say he showed good humor and moved under his own strength.

Rehnquist's illness has led to speculation that he will step down, giving the court its first opening since 1994. While such an announcement could come at any time, justices typically wait until the term ends at the end of June to leave. Traditionally, the aim of that timing strategy has been to avoid an extended vacancy and the possibility of 4-4 votes.