Two years ago, Gov. Gavin Newsom of California vowed on national television that if Senator Dianne Feinstein stepped down early, he would appoint a Black woman to replace her.
It was a promise that was only theoretical at the time even though questions were already emerging about the fitness of Ms. Feinstein, who turns 90 next month, to serve out her term. But after Ms. Feinstein contracted shingles earlier this year, was homebound and then returned to Washington frailer than ever, the contingency plan has become far more pressing — and more politically complicated.
A heated 2024 campaign to replace Ms. Feinstein is already underway, featuring three heavyweights from the California congressional delegation: Representative Katie Porter, a favorite of the progressive left; Representative Adam Schiff, who earned national fame managing the first impeachment of former President Donald J. Trump; and Representative Barbara Lee, the only Black woman of the three, who is best known for casting the lone vote in Congress against the war in Afghanistan more than two decades ago.
Now, if a vacancy comes, Mr. Newsom would have to decide whether to elevate Ms. Lee over her white rivals or find a caretaker who would agree not to seek a full term in 2024, presuming he keeps his pledge.
“The hard part now is the race is not that many months away, right?” Mr. Newsom said in a local television news interview this month about the upcoming Senate election. “The primary is early next year so it’s now a very different place — it’s not an academic conversation, like it was a year ago.”
Black leaders are watching closely. “The one thing we have as political people is our word,” said Lori D. Wilson, the chair of the California Legislative Black Caucus, who supports the appointment of Ms. Lee.
Mr. Newsom has already appointed one United States senator, replacing Kamala Harris, after she became vice president, with Senator Alex Padilla, who is California’s first Latino senator. The decision in December 2020, however, left no Black women in the Senate, disappointing Black leaders and party activists.
Nearly three months later, Mr. Newsom promised to appoint a Black woman to replace Ms. Feinstein, if she ever were to resign, during an interview on MSNBC with Joy Reid, the network’s most prominent Black woman anchor.
Ms. Feinstein has given no indication that she plans to step down even as her condition has plainly worsened. A New York Times report this week revealed that Ms. Feinstein had suffered from encephalitis, a previously undisclosed complication of the bout of shingles that kept her away from the Senate for more than two months. The condition, which is characterized by swelling of the brain, can result in lasting memory or language problems.
Mr. Newsom has expressed his wishes for her improved health, calling her “a mentor and a friend.” But he cannot escape the political ramifications if she were to leave office early, since he would be forced to pick her replacement.
“I hope I’ll never have to make that decision,” Mr. Newsom said last month.
Decades apart in age, Mr. Newsom, 55, and Ms. Feinstein both cut their teeth in bare-knuckle San Francisco politics and they have mostly been allied, with a notable exception coming in 2004 after Mr. Newsom decided to issue gay marriage licenses in City Hall. When Democrats suffered losses that fall, including the White House, Ms. Feinstein blamed the mayor obliquely for motivating conservatives, calling it “too much, too fast, too soon.”
Garry South, a Democratic political consultant who worked in the administrations of former governors in California and Ohio, says Mr. Newsom’s dilemma recalls what he describes as the poisoned chalice of political appointments.
“It’s kind of a no-win situation,” he said of Mr. Newsom’s choice of candidates. “When you appoint somebody to office you get one ingrate and nine people who are pissed off at you.”
Mr. South, who once served as a campaign manager for Mr. Newsom, predicted that the governor would not “put his thumb on the scale” among the three candidates.
“I think he would be perfectly excused for appointing a caretaker until the Democrats can sort out which of these three major Democrats they want to move onto the general election,” he said.
Even the notion of appointing a caretaker can be fraught.
Mr. Newsom, who has spoken little in public about whom he might appoint, has seen up close that short-term appointees do not necessarily keep their word. When he left San Francisco’s mayoralty, Mr. Newsom backed Ed Lee as his interim replacement. At the time, Mr. Lee promised not to seek a full term but he eventually did.
Some allies of Ms. Lee, who is not related to Mr. Lee, have publicly ratcheted up pressure for Ms. Feinstein to resign, most notably Representative Ro Khanna of California. But Nancy Pelosi, the former House speaker who has endorsed Mr. Schiff for Senate, has rejected calls for Ms. Feinstein to step down as sexist.
Mr. South points out that from a horse-race standpoint, Ms. Lee is polling in the single digits in early polling, running third behind Mr. Schiff and Ms. Porter. “What kind of sense would it make to elevate a candidate in a distant third position over the other two better-known, better-polling candidates?” he said.
The situation is further complicated by the fact that Mr. Newsom’s own circle of political strategists have split loyalties.
The firm of his longtime advisers, Ace Smith and Sean Clegg, is working for a pro-Schiff super PAC. His former spokesman, Nathan Click, is advising Ms. Porter. Two other Newsom strategists, Dan Newman and Brian Brokaw, are working for a pro-Lee super PAC.