Gavin Newsom’s new headache? A Democrat from Silicon Valley

SAN FRANCISCO — Gavin Newsom has a new tormentor, and it’s not a Trump follower, let alone a Republican. It’s the Democratic mayor of San Jose, the largest city in the famously progressive Bay Area, who is increasingly becoming a thorn in the California governor’s side.

Matt Mahan, a moderate from the heart of Silicon Valley, has pilloried Newsom for his social media strategy trolling Republicans. He’s lit into the governor for his handling of the state's problems with drug addiction and homelessness. And he has repeatedly chastised Newsom for his social media posts mocking Bed Bath & Beyond after the retailer said it wouldn’t open any stores in California due to the state’s regulatory climate.

When Newsom snarked on X about “the company that already went bankrupt and closed every store across the country two years ago,” Mahan not only jabbed at the governor on social media, but penned a blistering op-ed for a San Francisco news outlet, arguing Newsom is too focused on partisan jousting at the expense of his day job.

“My disagreements with the governor are not personal and they’re not particularly political — they are practical,” Mahan told POLITICO. “I would like to see our governor be laser focused on addressing the basics.”

He added, “I fear a politics that devolves into pure rhetoric, partisan bickering.”

At the moment, it’s Mahan doing the antagonizing — and not without consequences for Newsom, a likely presidential candidate in 2028. Past presidential runs are littered with home-state haters who turn into quote machines for unflattering assessments of candidates — all the juicier if they hold a respectable title in the same party. And in the run-up to 2028, the Democratic mayor of San Jose is emerging as one of the most outspoken critics of Newsom from within his own party.

His critique of Newsom cuts at one of the governor’s key vulnerabilities, the nagging suspicion that he is more interested in showmanship than following through on complex policy problems.

Mahan equated comments from Newsom and his press team about Bed Bath & Beyond to “political theater that serves to excuse inaction and ineffective policies” — the type of takedown from a fellow Democrat that Newsom’s opponents could use to cut attack ads in the thick of a presidential campaign.

Bob Salladay, Newsom’s spokesperson, said the governor’s parodying of Trump on social media is a small part of his strategy to push back against the president’s policies. Newsom himself has said his goal is to “put a mirror up” to the outrageousness of Trump’s behavior and the MAGA movement.

But Newsom’s office has mostly ignored or dismissed Mahan’s attacks: “We’re not at war with the mayor, no matter how hard he tries,” Salladay said. “We’re all in this together.”

That’s not how some of Newsom’s allies and longtime Democratic strategists in California see it, however, bristling at the frankness of Mahan’s swipes at the governor. They note progress under Newsom’s watch: Crime has fallen in many cities, and the state has slowed the growth of its homeless population. Newsom’s administration has also earmarked billions of dollars to help cities open homeless shelters and expand addiction treatment. And if Newsom’s polling numbers recently are any indication, Mahan’s view of Newsom, among Democrats, is in the minority.

“If Mahan wants to be the puppy peeing on Newsom’s carpet, bless him,” said Garry South, a longtime Democratic strategist who has previously advised Newsom. “He’s playing way out of his league.”

Mahan’s bravado has stirred speculation about his own aspirations. He has not ruled out running to succeed Newsom in 2026, though he would be a latecomer to a crowded gubernatorial field that has already drawn heavyweights like former Rep. Katie Porter and former Health and Human Services Secretary Xavier Becerra. Some progressive labor unions and activists have painted Mahan, a former tech executive, as a conservative masquerading as a liberal mayor.

Another Newsom adviser, who was granted anonymity to speak frankly about a sensitive topic, cast Mahan’s criticism in that light, suggesting the mayor is using Newsom as a foil to build his name recognition beyond San Jose — a large city that, despite its size and tech prowess, has birthed few statewide political stars relative to San Francisco, its hipper neighbor to the north.

“He comes from a long line of people who’ve tried to break out of San Jose,” the adviser said. “He’s trying to get attention by contrasting in a way that alienates base Democrats. Running against Gavin Newsom as a Democrat only makes sense if you plan to become a Republican.”

Still, Mahan’s critiques highlight a potential vulnerability for Newsom’s presidential campaign-in-waiting, amplifying a complaint — mostly from Republicans — that Newsom should spend less time brawling with Trump and focus more on solving California’s biggest problems.

Steven Maviglio, a veteran Democratic strategist and frequent critic of the governor, credited Mahan for voicing a complaint that “Newsom has neglected his job as governor and is totally focused on his presidential ambitions.”

He said, “It seems like a work horse criticizing a show horse.”

The origins of Mahan’s split with Newsom appear to date to a contentious 2024 ballot measure that toughened prison sentences for many drug and theft-related crimes. Newsom unsuccessfully tried to keep the measure off the ballot while Mahan became the public face of the Yes campaign, which voters passed by a landslide last fall.

Mahan wasn’t the only blue-city mayor to buck Newsom by backing the tough-on-crime measure, but he was the most vocal. He led a fundraising committee in support of the effort, stumped for it around the state and appeared in campaign ads.

Newsom made no attempt to hide his frustration with Mahan, suggesting the mayor was “lying” to voters by minimizing the punitive nature of the initiative. Last year, when Newsom traveled to a Home Depot in San Jose to sign a package of anti-theft bills, Mahan wasn’t invited to the ceremony in his backyard, even though he supported the legislation.

Now that the tough-on-crime measure, Proposition 36, has taken effect, the bad blood has only worsened. Mahan has repeatedly accused Newsom of not providing enough funding to help cities and counties implement the law and divert more offenders into addiction treatment. He argues Newsom is ignoring a “mandate” from voters.

Newsom’s office countered that San Jose never applied for any treatment funding available through an existing grant program. The mayor’s office, in turn, contends that it wouldn’t have, as behavioral health is the county’s responsibility.

The tension over Prop 36 flared up in recent days after Newsom’s team alleged that Mahan’s city had passed up the opportunity to seek treatment funding. The mayor argued that rationale from the governor’s office — that he should have competed with his county for funding — is the “exact line of thinking that leads to a government that spends more and accomplishes less.”

“I do not believe that Sacramento holistically is doing what needs to be done on homelessness, public safety and cost of living,” Mahan said. “We are desperate for leadership in Sacramento that only the governor can provide.”

The mayor is also throwing cold water on Newsom’s top political priority of the moment, a ballot measure to redraw California’s congressional map to offset the GOP’s gerrymander in Texas. While most Democratic officials are helping to campaign, Mahan is dunking on the measure, Proposition 50, from the sidelines.

“I will hold my nose and vote for Prop 50, but I don’t believe it’s something we should be proud of,” he said in a statement. “It’s not good governance to allow politicians to pick their constituents.”

But if Mahan’s criticisms of Newsom represent a potential liability for the governor, they are also generating attention for Mahan. His spat with Newsom is just one of the splashy moves that has bolstered his profile in recent months. Earlier this year, he unveiled a headline-grabbing plan to arrest homeless people who repeatedly refuse shelter, and similarly irked many liberals with his effort to tie some city employees’ pay raises to performance metrics.

Asked about the governor’s race, Mahan said he’s met with several candidates. Like with the current governor, though, he doesn’t seem impressed.

“I’m focused on running San Jose, but increasingly I’m running into roadblocks that require state action,” he said. “Frankly, I haven’t yet been blown away by what I’ve heard from any of the folks that have been running.”