How common are such lapses? One answer comes from an experiment by the 9th Circuit. In 2001, the appeals court set up a confidential help line for judges, expecting most calls to be about depression or addiction. Instead, the overwhelming majority have come from judges concerned that elderly colleagues were showing signs of slipping, said Richard Carlton, the consultant who answers the line. He said that each year he receives calls about six to eight judges within the circuit whose "mental acuity or change in temperament, or other changes in behavior are troubling."
Beyond the help line, and the informal pressure of chief judges, the more formal remedies have little effect. The last impeachment for mental incapacity was in 1803. Judges also can be stripped of their dockets if a committee of their peers votes to issue a certificate of disability. That has happened just twice in the last 20 years. Fewer than 1 percent of the 5,277 complaints from litigants and lawyers against judges, filed from 2000 to 2005, involved allegations of mental disability. Generally protective of the bench and fearful of a backlash, lawyers rarely complain.
Without clear rules or a protocol to guide them, some judges initiate their own early-warning system, asking colleagues or a former clerk to let them know if they are slipping. Judge Weinstein of Brooklyn gets an annual neurological checkup, including a CAT scan. In an interview, he suggested that the judiciary should consider amending its ethical code to encourage judges to notify their chief judge about health concerns, particularly if they are taking medications that affect memory or emotional balance.
Judge Martin of the 6th Circuit would go further: He thinks regular mental and physical checkups for senior status judges should be required. "Shouldn't you take that extra step of letting the government make sure you're as agile as you thought you were?" he asked.
Karen Williams knows firsthand what it means for a judge to face mental decline. While she doesn't support mandatory testing, she said she wouldn't object to a guideline that encouraged judges to consider regular exams. Named to the 4th Circuit at age 40, Williams was seen as a rising star, possibly even a Supreme Court candidate, until 2009. That's when she began to notice changes in herself. She struggled with spatial distortion. Even in familiar places, she couldn't remember which way to turn when she left a room. Stunningly, at age 57, Williams was diagnosed with Alzheimer's.
There was no roadmap for what to do next. Could she continue working until her symptoms worsened? For how long? "I questioned how and who would determine when I reached the stage that my mental processes truly were affected to such a degree as to make me unfit to remain on the bench," she said in a written response to my questions in the most detailed public account she has given about her diagnosis. "Would it require daily, weekly, monthly testing? What kind of testing? What test result would be needed to equate with 'unfitness'?"
Though she still felt able to perform her duties, after reflection Williams decided to retire immediately. "It was inappropriate to continue working, knowing that at any time any opinions I wrote or joined could be challenged or second-guessed," she told me. She added that she "did not want to harm in any way the dignity of the court." Without rules or a policy to guide her decision, Williams had to make her own call. She decided to put the court first. But she may be more the exception than the rule.
ProPublica intern Joseph Kokenge contributed to this report.
Like Slate on Facebook. Follow us on Twitter.