Less than an hour after a gunman in Butler, Pa., tried to assassinate Donald J. Trump this month, David Sacks, a venture capitalist based in San Francisco, directed his anger about the incident toward a former colleague.

“The Left normalized this,” Sacks wrote on X, linking to a post about Reid Hoffman, a technology investor and major Democratic donor. Sacks implied that Hoffman, a critic of Trump who had funded a lawsuit accusing the former president of rape and defamation, had helped cause the shooting.

Elon Musk, who leads SpaceX and Tesla and previously worked with Sacks and Hoffman, then weighed in on X, name-checking Hoffman and saying people like him “got their dearest wish.”

In Silicon Valley, the spectacle of tech billionaire attacking tech billionaire has suddenly exploded, as pro-Trump executives and their Democratic counterparts have openly turned on each other. The brawling has spilled into public view online, at conferences and on podcasts, as debates about the country’s future have turned into personal broadsides.

The animus has pit those who once worked side by side and attended each other’s weddings against one another, fraying friendships and alliances that could shift Silicon Valley’s power centers. The fighting has been particularly acute among the “PayPal Mafia,” a wealthy group of tech executives — including Hoffman, Musk, Sacks and the investor Peter Thiel — who worked together at the online payments company in the 1990s and later founded their own companies or turned into high-profile investors.

Other tech leaders have also been pulled into the political spats, including Vinod Khosla, a prominent investor, and Marc Andreessen and Ben Horowitz of the Silicon Valley venture firm Andreessen Horowitz.

Their unabashed vitriol is stark. While tech leaders often criticize one another in private, they rarely do so publicly for fear of upsetting a potential deal partner or future job prospect.

“Until a year or two ago, there was something like an omertà in Silicon Valley,” said Roger McNamee, a Silicon Valley venture capitalist, using a word popularized by the Italian mafia for a code of silence. “People had fights all the time and leaders would disagree, but you wouldn’t disagree in public.”

McNamee jumped into the rumpus on Wednesday by calling out Andreessen and Horowitz, who both recently endorsed Trump, for their “antidemocratic” values on X. McNamee had previously invested in a company that  Horowitz led.

Horowitz shot back on Thursday, invoking his 25-year business relationship with McNamee. “Really Roger?” Horowitz wrote. “Your very first idea when we disagree is to attack me in a tweet?”

The altercations show how Silicon Valley’s identity is fragmenting. For years, the nation’s tech capital was seen as a liberal bastion. But Sacks, Musk, Andreessen and Horowitz all broke from that view by endorsing Trump in recent weeks.

Many of them were unhappy with President Biden’s tech policies and regulatory appointees, who have pursued more rules and lawsuits against tech companies. They prefer Trump for his push to lower taxes and his support for the cryptocurrency industry, which some of the tech billionaires have invested in.

“There’s been shaming and canceling on the left for some time,” said Trevor Traina, a Republican in San Francisco who served as ambassador to Austria during Trump’s presidency and is close to Sacks and Hoffman. “And now you’re starting to hear strong voices on the right in Silicon Valley.”

Democratic tech executives and investors have countered that Trump is not good for tech. They say Trump and his allies have talked about throwing Mark Zuckerberg, the chief executive of Meta, in prison; suggested breaking up big tech companies; and proposed strict immigration policies, which could hinder the industry’s hiring of skilled workers.

Hoffman, Thiel and an Andreessen Horowitz representative declined to comment. Sacks and Musk did not respond to requests for comment.

Political tensions began escalating into personal attacks last month after Sacks held an ornate fund-raiser for Trump in San Francisco. Days later, Hoffman, who gave at least $10 million to bolster President Biden’s campaign, chided Sacks in a blog post for following “pro-Trump groupthink” and backing “a convicted felon.”

At a conference in Sun Valley, Idaho, this month, Hoffman got into a heated exchange with Thiel, who has funded Republicans, according to a person briefed on the conversation. The longtime friends bickered over Hoffman’s stance against Trump, leading Hoffman to sarcastically say that he wished he had made the former president “an actual martyr,” the person said. The exchange was reported earlier by Puck.

After the assassination attempt on Trump, Sacks and Musk used Hoffman’s words to criticize their former colleague. Hoffman responded last week by pointing out that some current supporters of Trump, including Sacks, had disavowed Trump in 2021 after the Jan. 6 riot at the U.S. Capitol.

“If you have integrity and you’re supporting Trump in this election, you should address that,” Hoffman said in a podcast appearance on Wednesday.

This month, Sacks shared a list of pro-Trump techies on X and spoke at the Republican National Convention, which grated on Democratic tech investors and entrepreneurs, said Siri Srinivas, an investor at Gradient Ventures. After President Biden withdrew from the race and Vice President Kamala Harris became the presumptive Democratic nominee, many of those investors and entrepreneurs were energized and felt more emboldened to speak out, she said.

“Weeks of private hand-wringing likely helped many to urgently and emphatically show their support for Harris and opposition to Trump,” Srinivas said. On Tuesday, she mimicked Sacks’s list by posting a roster of the industry’s Harris supporters on X.

Sacks has since continued his verbal attacks, taking aim last week at Reed Hastings, a Netflix founder who is a major Democratic donor. On X, Sacks called Hastings a “useful idiot” for supporting the Democratic Party.

Hastings did not respond to a request for comment.

Some tech luminaries have stayed out of the fray, including Zuckerberg. In 2016 when Trump was elected, Zuckerberg posted on his Facebook page that “progress does not move in a straight line,” alluding to Trump without naming him. But this time, the Meta chief has not talked about politics.

The exception was an interview with Bloomberg this month, in which Zuckerberg complimented. Trump’s “fist-pump” moment after the assassination attempt. Zuckerberg’s decision to take a less vocal approach to politics could improve strained relationships in Washington and potentially with Trump if he is elected, two people familiar with the discussions said.

A Meta spokesman declined to comment.

Some tech entrepreneurs are reacting to the politicking. Merci Grace, a start-up founder in San Francisco, said she felt “betrayed” by Andreessen’s and Horowitz’s endorsements of Trump and would not work with their venture firm. Grace, who supports abortion rights and once had surgery after a life-threatening ectopic pregnancy, said she opposed the stance against abortion from JD Vance, Trump’s running mate.

“The way in which Ben and Marc are claiming they’re single-issue voters for Trump is so galling to me, because men have been throwing that line in my face for years as a way to dismiss the life-or-death stakes of abortion access,” Grace said, referring to the investors’ support of Trump because of what they said were his pro-tech policies. “Yes, I’m a single issue voter, too. Being alive is my issue.”

But Khosla, who supports Harris, said the fights over politics would not leave lasting fractures in the tech industry, where innovation ultimately reigns supreme.

“I’ll work with almost anyone if what I’m working on can change the world,” he said.

Ryan Mac, Erin Griffith and Mike Isaac are California reporters for The New York TImes. Copyright, 2024, The New York Times.