Boston ? I can only imagine what William Rehnquist thinks of all this. When he first became chief justice, a reporter asked about updates on the health of the justices. He shot back: “You people can be like a bunch of vultures.”

Does Rehnquist see vultures circling over his black robe as he returns to work part-time: Will he be in court for the new session on Monday? Will he swear in the president on Jan. 20, as he has promised?

There is something unseemly about the endless speculation on the health of Supreme Court justices. This once prodded Sandra Day O’Connor, a breast cancer survivor, to issue a statement saying, “I am not sick. I am not bored. I am not resigning.”

But since October when the pale and hoarse chief justice was last seen in court, privacy has seemed more like secrecy. The first report announced tersely that Rehnquist had a tracheotomy “in connection with a recent diagnosis of thyroid cancer.” The second said he was being treated with radiation therapy and chemotherapy.

Doctors speculate out loud that the 80-year-old justice has a deadly form of thyroid cancer. But Rehnquist, reportedly declining visits from other court members, has said only that he won’t vote in every case this term unless it is to break a tie. He will “participate” in 12 cases though he missed the oral arguments.

Is that all we are owed by the head of one of our three branches of government? The branch with lifetime tenure?

In these same months, we were told the result of the president’s annual physical down to his weight gain and hearing loss. We knew when Dick Cheney’s cold took him to the hospital. We read details on Condoleezza Rice’s uterine fibroids.

But we don’t know if the Supreme Court has eight or nine operating justices. We have no way of knowing if the chief is fit.

“Unlike anyone else with political power,” says the University of Chicago Law School’s Dennis Hutchinson, “the judges don’t have to tell us when they are fit and how fit.” Since the justices serve “during good behavior,” the only way they leave the lifetime job is impeachment — “the 400 megaton solution” — or resignation.

It is, in essence, up to the justice to say if he or she is up to the job. But the record is not that reassuring.

In American history, 15 justices stayed on the bench beyond their mental abilities. In the most dramatic cases, Henry Baldwin was hospitalized for “incurable lunacy” in 1833 and Frank Murphy was hospitalized for dependency on barbiturates and narcotics in 1947. Others simply sat beyond the point of dementia.

In the last 50 years, says historian David Garrow, there were half a dozen “instances in which serious questions were or should have been asked about whether judicial votes were being cast by a less-than-fully-competent justice.”

Charles Whittaker had a nervous breakdown in 1957. William O. Douglas refused to retire after a severe stroke in 1974. Thurgood Marshall stayed beyond his ability. So did Hugo Black, the justice who once told his clerks that “one of the hardest things you have to do up here … is to know when to leave.”

Early in his tenure, Rehnquist, who suffers chronic back problems, became so dependent on Placidyl that the doctor said he had “disturbances in mental clarity.” Nevertheless, when he was up for chief justice, he told the Senate Judiciary Committee, “So long as I can perform my duties, I do not think I have any obligation to give the press a health briefing.”

I sympathize with the passion for privacy. These justices don’t even want cameras in the courtroom. But what checks are there on the men and women who have a quasi-royal role in a democracy?

We’ve had two failed attempts to institute mandatory retirement at 75. Term limits are now being promoted by a handful of professors. More realistically, Hutchinson and Garrow talk about having Congress mandate an annual exam for physical and neurological health.

These options all come with flaws and a measure of indignity. After all, at 84, Justice Stevens still jogs two miles. As for the annual physical, who would judge that exam? Three other justices have had cancer and returned to health. We have no reason to believe that Rehnquist is too ill to serve. And no reason to believe that he isn’t.

As Garrow says, “The American people are owed significantly more forthcoming information about the treatment and prognosis than they’ve been given.” It’s not the vultures, it’s the American people.

In his year-end letter, Rehnquist mentioned his illness only to thank those who wished him a speedy recovery. Amen to that. But thank-yous are not enough.

— Ellen Goodman is a columnist for Washington Post Writers Group.