EDITOR’S NOTE: Multimedia journalist Logan Hall spoke with an undecided Democratic voter about who he thinks could replace Sen. Dianne Feinstein. Click the arrow above to watch the video.

LOS ANGELES (AP) — U.S. Sen. Dianne Feinstein’s ongoing medical struggles have raised a sensitive political question with no easy answer: Who would California Gov. Gavin Newsom pick to replace her if the seat becomes vacant?

Despite calls from within her own party to resign, Feinstein, who turns 90 next month and is the oldest member of Congress, has given no indication that she is considering stepping down. Her frail appearance, confused interactions with reporters in Washington and the growing list of health challenges disclosed by her office continue to fan questions about her fitness for the job — now and into the future.

Should a vacancy occur, a range of names, from obscure to famous — including Oprah Winfrey — have been floated in California circles as possible replacements. Newsom, who is mentioned as a possible future presidential contender, would also have to deal with political complexities, some of his own making: In 2021 he promised to appoint a Black woman should Feinstein's seat become open. Meanwhile, a 2024 Senate campaign is underway to fill the seat when the senator’s term ends in January 2025.

The situation has created a sad, public coda for the groundbreaking career of a Democratic leader who shattered gender barriers in California and Washington.

Here’s a look at what could happen:

What is the status of Feinstein's health?

In short, much is unknown.

Feinstein returned to the Senate on May 10 — about 10 weeks after being diagnosed, then briefly hospitalized, with shingles in San Francisco. On her return to the Capitol, she was markedly thinner and one side of her face was drooping, apparently from Ramsay Hunt syndrome, which can occur when the shingles virus reaches a facial nerve near the ears. It also can cause hearing loss.

On the advice of doctors, Feinstein's staff say she is working a lighter schedule as she deals with side effects from the virus, including vision and balance problems. She has been using a wheelchair to get to her office and committee meetings.

Questions have been raised in recent years about Feinstein's memory and mental acuity, though she has defended her effectiveness. Since her return to Washington, she has at times appeared confused during brief discussions with reporters. Her office also disclosed she suffered a bout of encephalitis, or inflammation of the brain, which can also be caused by shingles.

Feinstein's biographer Jerry Roberts told the Los Angeles Times in an interview published Sunday that the senator has “a belief in herself to the point of stubbornness, where nobody is going to tell her what she can or cannot do. She has tremendous belief and confidence in her own strength and her own ability.”

Newsom's promise: Elevating a Black woman to Senate

When California Sen. Kamala Harris resigned to become vice president, Newsom faced pressure from both Black, Latino and other groups over a replacement pick. Some felt that he should replace Harris, the only Black woman in the U.S. Senate, with another Black woman. But others thought it was past time for California to have its first Latino senator, and Newsom chose then-Secretary of State Alex Padilla for the job.

But he later promised that if Feinstein's seat became vacant, he would choose a Black woman to replace her. Should Feinstein step aside, he'll be expected to make good on the promise.

“He made the commitment and I do not believe there is any wiggle room for the governor not to honor his commitment,” said Kerman Maddox, a Los Angeles-based Democratic strategist and fundraiser who is Black.

“Newsom must honor his promise to appoint a Black woman" if Feinstein resigns, said Democratic Assemblymember Lori Wilson, who heads the Legislative Black Caucus in Sacramento. "I trust him at his word. We currently have zero Black women in the Senate, so if the opportunity becomes available the governor must act to help remedy this lack of representation.”

Claremont McKenna College political scientist Jack Pitney pointed out that any presidential ambitions that Newsom might harbor would be damaged if he backed away from his promise to name a Black woman, noting that the candidate favored by Black voters has won the Democratic Party's presidential nomination for every cycle since 1992.

“The last thing you want to do if you are thinking about running for president is alienating the nominating wing of the Democratic Party,” Pitney said.

Which way to turn — caretaker or contender?

In filling a Senate vacancy, Newsom has the authority to name a successor. He could even pick himself, though that is unlikely. State rules dictate when an election would have to be held.

Newsom's choices all run risks.

He could get entangled in the ongoing Senate campaign and choose one of the declared candidates to fill a Feinstein vacancy.

Another option would be to select a caretaker, and then leave it to voters to decide in next year’s election — someone who would hold the seat but is not a Senate candidate. That's where names like Winfrey come up — a celebrity who is Black and happens to meet Newsom's appointment pledge. However, Newsom also might find it challenging to land on someone willing to take a short-term appointment.

If he picked one of the declared Senate candidates, Newsom would unsettle the growing field and elevate that person to frontrunner status. U.S. Rep. Barbara Lee, who is Black, is already running against fellow Democratic Reps. Katie Porter and Adam Schiff, who both are white.

Lee “is far and away the most qualified African American woman to replace Sen. Feinstein if a vacancy becomes available,” Maddox said.

In a recent interview with Fox 11 TV in Los Angeles, Newsom said he was being swamped with recommendations for how to fill a possible Senate vacancy. He calls Feinstein a mentor and one of his closest friends, and said he was hoping he never had to make a decision to fill her seat.

He noted that the primary was quickly approaching in March, and added that he was sensitive to criticism that voters should be picking their elected officials, hinting that he might choose a caretaker to hold the spot, if one occurs.

“I get it. For those who say, 'Enough of Newsom making these picks!' I get it. I'm with you. I understand,” he said.