‘Like Two Cats Circling’: Kamala Harris and Gavin Newsom Weigh a 2028 Showdown

They drew broad notice in the 2003 San Francisco election, leading an up-and-coming generation of California politicians—Newsom as mayor and Harris as district attorney—by turns bumping elbows over command of the microphone at news conferences.

Newsom, 58 years old, and Harris, 61, have shared mentors, staffers, donors, friends and consultants for more than two decades, going neck and neck in the parochial world of Bay Area politics. They have exchanged endorsements and snubs, each wary of the other, according to people close to both.

“They’ve been kind of like two cats, circling each other in an alley for years, politically speaking,” said Democratic strategist Garry South, who worked for Newsom.

The conspicuously liberal politicians live in exclusive locales at two ends of the Golden State —Harris in Malibu, Calif., and Newsom in Marin County—and appear on a collision course for the keys to the big white mansion at 1600 Pennsylvania Avenue.

“Their trajectories have been so fast and put them in places of such prominence, there’s only one step up electorally for either of them at this point,” said Brian Brokaw, a Democratic consultant who has worked for both.

Newsom, who is wrapping up his second term as California governor, is widely expected to mount a 2028 presidential bid. People close to Harris say she is undecided, still stung by her 2024 loss to President Trump. In April, Harris got a warm reception in New York from Black activists who chanted Run again! Run again! “I might,” she said. “I’m thinking about it.”

Most early Democratic primary polls show them holding top slots in the field of potential presidential candidates, in what would be their first head-to-head contest.

In recent months, they have been on dueling book tours. Harris, promoting her book, “107 Days,” sold out event spaces around the U.S. more than six months after its publication.

Newsom later released his own book, a memoir titled “Young Man in a Hurry.” He, too, made the rounds in a promotional tour that included New York, South Carolina and Georgia.

Their respective teams keep an eye on the other’s book sales, said people familiar with the matter. The former vice president’s book, which was released in September, has sold more than 385,000 copies through May 23, according to data from Circana BookScan. Newsom’s book, released in February, has sold more than 100,000 copies in close to 13 weeks.

Both of their PACs reported buying and distributing books to supporters—Newsom’s spending $1.6 million the week his book went on sale. Harris’s PAC spent $97,000 buying her books during the month Newsom’s memoir launched.

Newsom told Axios he had only read excerpts of Harris’s book but heard it sold “unbelievably well.” Harris has said nothing publicly about Newsom’s.

The governor cited a dig in Harris’s book. Harris wrote that she called Newsom to secure his support after former President Joe Biden’s abrupt exit from the 2024 race. The governor texted, “Hiking. Will call back,” according to Harris’s account, but he never did.

Newsom has since said he did text Harris, saying he had already put out a statement supporting her and that he was the last person she needed to talk to.

The governor said in an interview last year with video streamer ConnorEatsPants that he messaged Harris asking why she wrote in her book that he never answered her.

Harris, he said, replied, “‘On book tour. Get back to you later.’”

“Anyway,” Newsom told the interviewer, “that’s the relationship.”

A month after Newsom’s alleged text snub, Harris was set to accept the Democratic nomination for president at the party convention in Chicago. She was surprised to see that Newsom was missing from the roster of speakers. Advisors told her that Newsom had declined a speaking slot because of a scheduling conflict, according to people familiar with the discussion.

Newsom, who long harbored his own ambitions to be president, considered the convention appearance on behalf of Harris about as appealing as giving a speech at the wedding of an ex, said people close to him, and he was happy to have an excuse to bow out gracefully. His aides told the Los Angeles Times that Newsom decided to instead take his children to a school orientation that day before flying to Chicago, the paper reported.

The governor appeared at the convention’s high point later that week. In a nationally televised moment, Newsom announced California’s delegate count, which secured Harris’s presidential nomination. He described Harris’s accomplishments and their decadeslong relationship. “Kamala Harris has always done the right thing,” he said.

Harris and Newsom’s spokespeople didn’t respond to requests for an interview.

“The Governor and the Vice President have known each other for decades—he has deep respect for her as a public servant, friend and colleague,” Newsom spokesman Nathan Click said in a statement, declining to comment on specific reporting about their relationship.

“The Vice President and the Governor have known and respected each other for decades,” a spokesperson for Harris said. “She has tremendous regard for the work he’s done and continues to do for California.”

Harris’s aides believed the results became a sensitive subject for Newsom’s team, which came to view Harris as a potential threat and future challenger, according to people familiar with their relationship at the time.

Former Newsom aides disagreed with that characterization and said Newsom didn’t see Harris as a threat. Newsom in his book described his margin of victory—6 percentage points—as a mandate.

Newsom’s then-wife, Kim Guilfoyle, had warned her husband to be wary of Harris’s intentions, saying Harris was neither a friend nor an ally, according to a person familiar with the conversation. The two women had earlier crossed paths while working as county prosecutors.

As mayor, Newsom liked to always speak first. So did Harris. If the mayor was late to a news conference, which was fairly often in those days, Harris would kick things off herself, according to their former aides. When Newsom arrived, Harris would sometimes point to her watch, teasing the governor for being tardy, aides said.

“At that early stage, they were both very aware that each other were political athletes, they could see the promise in each other, so they were friendly rivals between both the district attorney’s and the mayor’s office,” said Joe Arellano, an aide to Newsom at the time.

Harris and Newsom had heated exchanges over the district attorney’s office budget, which Newsom largely controlled, the people familiar with their relationship said. The arguments continued backstage before public events, said people who heard them.

Guilfoyle, who was divorced from Newsom in 2006, campaigned against Harris on behalf of Trump in the 2024 presidential campaign. The president later nominated Guilfoyle, for a time Donald Trump Jr.’s fiancée, as U.S. ambassador to Greece, a job she currently holds.

When Newsom and Harris were in their second terms, Democrats prepared to nominate Barack Obama as their standard-bearer at the party’s 2008 national convention in Denver.

During convention week, Harris and Newsom appeared at a Time magazine panel featuring politicians selected by the magazine as “Hotshots to Watch.” Obama had been on the same panel at the 2004 convention, and the event was seen as a high-profile audition for the gathered media and political elite.

Privately, Harris complained about Newsom’s inclusion, according to people who attended the convention. As she spoke on stage about the need to reform prosecutions of low-level drug offenders, Newsom interrupted her, saying “I agree with my DA, which is always a good thing.”

“Yes, it is,” Harris said.

Newsom spent days talking strategy with his team, which included some of the same political consultants who worked with Harris. He decided to forgo a Senate run, hinting he would instead wait two years to run for governor.

Newsom phoned Harris to let her know before announcing his decision, according to people familiar with the discussions. Harris didn’t pick up.

A day later, Harris launched her bid for Boxer’s seat. She and Newsom told aides they made their decisions independently of each other. Newsom endorsed Harris in her successful 2016 Senate campaign. She later did the same for Newsom in his winning gubernatorial race.

During Harris’s campaign for the 2020 presidential election, Newsom told her team he would endorse her in the California primary but kept putting it off, according to people familiar with the discussions. He gave an endorsement only when asked directly in an MSNBC interview, a question that had been suggested to news producers by a Harris aide, those people said.

Newsom didn’t spend as much time campaigning or fundraising for Harris as her campaign wanted. When Newsom did occasional interviews on her behalf, he also touted her Democratic rivals. Harris dropped out in December 2019, and Biden picked her as his running mate months later.

As vice president, Harris was wary when sharing the stage with the California governor.

At a 2022 event in San Bernardino regarding the Biden administration’s investments in wildfire prevention, Harris questioned her staff about what Newsom planned to say, according to people familiar with the matter. The vice president made clear she didn’t want Newsom taking over the event, insisting she speak last because she held the higher post, these people said.

After Harris left office, Trump revoked her Secret Service protection before she embarked on her national book tour. Newsom, whose spokesperson called the president’s decision “vindictive,” provided Harris security protection by California Highway Patrol officers.

In recent months, Newsom and Harris have spoken to Democratic activists at large events across the U.S. and raised funds for the party. Harris has headlined state party events in the South, where she maintains support among Black voters, a key Democratic constituency.

Some Harris and Newsom supporters have already decided which of the two they would support should both decide to run. But most aren’t saying so publicly, hoping to avoid the discomfort of giving the bad news to one or the other, according to donors and advisers. The conflict is expected to be much worse for the two candidates.

Sean Clegg, who served as a political adviser to both Newsom and Harris, warned of the expected ferocity of such a battle in the San Francisco Chronicle a dozen years ago.

“If they ever run in the same race,” Clegg said, “it will be a murder-suicide. God forbid.”

Write to Tarini Parti at tarini.parti@wsj.com and Eliza Collins at eliza.collins@wsj.com