When she arrived at the Capitol last week after a more than two-month absence recovering from shingles, Senator Dianne Feinstein, Democrat of California, 89, appeared shockingly diminished.
Using a wheelchair, with the left side of her face frozen and one eye nearly shut, she seemed disoriented as an aide steered her through the marble corridors of the Senate, complaining audibly that something was stuck in her eye.
Ms. Feinstein’s frail appearance was a result of several complications after she was hospitalized for shingles in February, some of which she has not publicly disclosed. The shingles spread to her face and neck, causing vision and balance impairments and facial paralysis known as Ramsay Hunt syndrome. The virus also brought on a previously unreported case of encephalitis, a rare but potentially debilitating complication of shingles that a spokesman confirmed on Thursday after The New York Times first revealed it, saying that the condition had “resolved itself” in March.
Characterized by swelling of the brain, post-shingles encephalitis can leave patients with lasting memory or language problems, sleep disorders, bouts of confusion, mood disorders, headaches and difficulties walking. Older patients tend to have the most trouble recovering. And even before this latest illness, Ms. Feinstein had already suffered substantial memory issues that had raised questions about her mental capacity.
The grim tableau of her re-emergence on Capitol Hill laid bare a bleak reality known to virtually everyone who has come into contact with her in recent days: She was far from ready to return to work when she did, and she is now struggling to function in a job that demands long days, near-constant engagement on an array of crucial policy issues and high-stakes decision-making.
In the statement provided after The Times’s article was published on Thursday, Ms. Feinstein’s spokesman acknowledged that the senator continued to suffer the effects of Ramsay Hunt syndrome. Her office declined to comment further for this article, beyond a statement from Ms. Feinstein saying: “I’m back in Washington, voting and attending committee meetings while I recover from complications related to a shingles diagnosis. I continue to work and get results for California.”
Many people close to Ms. Feinstein, a six-term senator, described seeing her operating in the Senate in her current state as “frightening,” a tragic end to a formidable career in politics that they worry is casting a shadow over her legacy and her achievements. More immediately, it has resurfaced questions about whether Ms. Feinstein, who has announced she will retire when her term ends next year, is fit to continue serving even for that long.
Ms. Feinstein, a pioneering woman in Democratic politics who was once a major party power broker and a legislative force in the Senate, has stubbornly refused to consider leaving. The same force of will that led her nearly a decade ago to resist pressure from the Obama administration to keep secret a damning torture report still rears its head when she is confronted with calls to step down. The senator still sees the job as her calling and is no more receptive to a conversation about stepping aside than she was in 2018, when she decided to seek another term despite questions about her mental acuity.
People close to her joke privately that perhaps when Ms. Feinstein is dead, she will start to consider resigning. Over the years, she and many Democrats have bristled at the calls for her to relinquish her post, noting that such questions were rarely raised about aging male senators who remained in office through physical and cognitive struggles, even after they were plainly unable to function on their own.
But after her latest illness, even some of Ms. Feinstein’s longtime allies have grown deeply uneasy about her situation.
“I admire the senator deeply, and I am sorry she is so not well,” said Susie Tompkins Buell, a major Democratic donor and a longtime Feinstein supporter. But she added: “The Senate has critical, challenging work to do, and as the stakes are so high and she is not able to be present, to be informed and active, let alone have the rest she needs in order to recover, I feel she needs to step down. And yet she isn’t willing in this state of mind.”
Ms. Buell said Senator Chuck Schumer, Democrat of New York and the majority leader, or Gov. Gavin Newsom of California, who would appoint a successor should Ms. Feinstein resign before the end of her term, have “the responsibility to do something.”
Neither has directly implored her to leave, as the senator has deflected almost every effort to have a serious discussion about her future.
At home in San Francisco during her recovery, Ms. Feinstein refused to have contact with California lawmakers who tried checking in with her. A call from Mr. Newsom on her personal phone was answered by an aide and went unreturned. An offer of an in-person visit from Senator Alex Padilla, Democrat of California, was flatly rejected. Even some family members who wanted to see her were turned away.
Throughout her latest health ordeal, Ms. Feinstein remained adamant about her need to return to work. She agitated to return to Washington as pressure mounted for her to step aside or physically show up to vote so that Democrats could advance President Biden’s judicial nominees and move ahead with their agenda in the closely divided Senate.
One person whose call she would take was Mr. Schumer, who in multiple conversations with Ms. Feinstein encouraged her to listen to the advice of her doctors. But when it became clear that she had no desire to discuss leaving office, Mr. Schumer began planning for her to return to Washington, according to several people familiar with the conversations.
“After talking with her multiple times over the past few weeks, it’s clear she’s back where she wants to be and ready to deliver for California,” Mr. Schumer said in a statement on the day of Ms. Feinstein’s return. He greeted her in front of the Capitol as an aide helped her from a car into her wheelchair.
With Ms. Feinstein’s return, Senate Democrats were able to advance three of Mr. Biden’s judicial nominees whose approval by the Judiciary Committee had been delayed because of her absence, which deprived her party of the majority it needed to move forward in the face of Republican opposition. Democrats greeted her in the committee with a standing ovation.
But Ms. Feinstein appeared confused about the warm greeting when a small group of reporters asked about it days later.
“I haven’t been gone,” she said. When pressed on whether she meant that she had been working from home, she pushed back in a manner that suggested she might not have been aware of her long and politically charged absence. “I’ve been here,” she said, appearing to grow agitated. “I’ve been voting. Please, either know or don’t know.”
Aides who themselves have come under criticism for allowing her to continue in her current state described Ms. Feinstein as still engaged and ultimately in charge of decisions that come out of her office. She reviews and approves work that her staff brings her, they say, and they do not shield her from the toughest news clips about her condition and the calls for her to step aside. But they have also acknowledged that she is not fully up to her senatorial duties; Ms. Feinstein has missed several votes since her return, and aides issued a statement saying she would be working on a “lighter schedule” given her continuing health challenges.
Ms. Feinstein flew on a chartered private plane last week to return to Washington, accompanied by her dog, her longtime housekeeper and Nancy Corinne Prowda, the eldest daughter of Representative Nancy Pelosi of California, the former House speaker who has been a longtime friend of Ms. Feinstein’s and has been practically living at her house during her recovery.
The senator’s relationship with Ms. Pelosi’s daughter goes back decades. The Pelosi family grew up across the street from Ms. Feinstein, people close to her said, and Ms. Prowda has been close with Ms. Feinstein since she was a child, looking up to her as a maternal figure.
But the senator’s condition and the political drama surrounding her fate has drawn so much scrutiny that even the presence of one of her closest friends during her convalescence has drawn speculation. Some have read Ms. Prowda’s involvement as a tacit endorsement by Ms. Pelosi of Ms. Feinstein’s decision to stay on, reasoning that it could give Representative Adam B. Schiff, Democrat of California and Ms. Pelosi’s chosen candidate in the crowded race to replace Ms. Feinstein in 2024, a leg up. Mr. Newsom has committed to appointing a Black woman to the seat should it become vacant.
But Ms. Prowda is not involved in politics at all and is as close to Ms. Feinstein as family.
Since Ms. Feinstein’s return to Washington, several of her colleagues have privately acknowledged that she is obviously diminished. She should probably not be in the Senate, they said, though Democrats are happy to have her vote when she can.
Ms. Feinstein was ailing before her latest setback. For years, she has sometimes struggled to recall the names of colleagues, frequently had little recollection of meetings or telephone conversations that just took place, and at times walked around in a state of befuddlement. Some lawmakers who have interacted with her have come away with serious concerns that she is mentally incompetent to serve. Others have hung up the phone after conversations in which she repeated the same comments several times in a row with no apparent awareness that she was doing so.
Shingles can potentially contribute to cognitive decline in a number of ways, including by damaging blood vessels of the brain, said Dr. Sharon E. Curhan, a physician and epidemiologist at Brigham and Women’s Hospital and Harvard Medical School who is studying the link between shingles and changes in cognition.
But there are few people in Ms. Feinstein’s circle who can persuade her that it is time to step down. A longtime friend, former Representative Ellen Tauscher of California, who was known as a “Feinstein whisperer,” died in 2019. Her husband, Richard C. Blum, passed away last year, a major setback for Ms. Feinstein.
Some current and former colleagues said the situation was alarming to watch and blamed Senate Republicans — who blocked Ms. Feinstein’s request for a temporary replacement on the Judiciary Committee — for upsetting images and sound bites of an infirm and confused senator trying to navigate the Capitol.
“Republicans are responsible for this nightmare scenario that’s unfolding,” said former Senator Barbara Boxer, who made history with Ms. Feinstein in 1992 as the first female senators elected from California. “I am sick at heart at that. I blame them for being mean to her and spinning it to blame the Democrats.”
Shawn Hubler contributed reporting from Sacramento, Thomas Fuller from San Francisco, and Benjamin Mueller from New York.