A Wall Street Journal investigation by reporter Keach Hagey, based on extensive interviews with current and former employees and people close to executives, discloses for the first time the decade-long personal feud between the founders of Anthropic and OpenAI. The shape of global AI is not just about technical disagreements—it's also about unhealed personal wounds.
Internal Fury: Hitler vs. Stalin, Evil Donations
According to the report, Dario Amodei's internal rhetoric has been far sharper than his public statements in recent months. He compared Sam Altman's legal battle with Elon Musk to "Hitler versus Stalin," called OpenAI President Greg Brockman's $25 million donation to a pro-Trump super PAC "evil," and likened OpenAI and other competitors to tobacco companies knowingly selling harmful products. After a Pentagon contract dispute escalated, he labeled OpenAI "mendacious" on Slack, writing, "These facts show a pattern I've seen repeatedly in Sam Altman."
The Origin: A 2016 Living Room Debate
The story begins in 2016 in a shared house on Delano Avenue in San Francisco. Dario and his sister Daniela Amodei lived there; OpenAI co-founder Brockman often visited due to his friendship with Daniela. One day, Brockman, Dario, and Daniela's then-fiancé, effective altruist philanthropist Holden Karnofsky, argued about the right path for AI development: Brockman believed the public should be informed about AI frontier progress, while Dario and Karnofsky argued sensitive information should first go to the government. This split later became the philosophical divide between the two companies.
Four Years of Tension: Power, Betrayal, and a Showdown
Dario joined OpenAI in mid-2016, training AI agents to play video games with Brockman late into the night. But over four years, conflicts over power and recognition deepened. In 2017, major backer Elon Musk demanded a list of each employee's contributions to justify layoffs; about 10-20% of the ~60-person team were fired one by one, which Dario viewed as cruel. One of those laid off later became an Anthropic co-founder. That same year, an ethics consultant hired by Dario proposed making OpenAI a coordination entity between AI companies and governments. Brockman stretched this into an idea of "selling AGI to nuclear powers in the UN Security Council," which Dario considered nearly treasonous; he briefly considered resigning.
After Musk's departure in 2018, Altman took over. He and Dario agreed that employees lacked confidence in Brockman and chief scientist Ilya Sutskever. Dario stayed on condition that the two would no longer manage, but soon discovered Altman had separately promised both men they could fire each other—contradictory commitments. When GPT development began, a fierce fight erupted over who could lead the language model project. Dario, as research director, barred Brockman from involvement; his sister Daniela threatened to quit, dragging the project into a proxy war.
As GPT-2 and GPT-3 succeeded, Dario's stature grew, but he felt Altman downplayed his contributions. He was furious when Brockman alone discussed the OpenAI charter on a podcast—Dario had contributed more but wasn't invited. The same resentment flared when Brockman and Altman met former President Obama without him. The breaking point came in a tense office meeting: Altman called the Amodei siblings in, accusing them of rallying colleagues to submit negative feedback about him to the board. They denied it. Altman claimed another executive had told him; Daniela summoned that executive on the spot, who denied any knowledge. Altman then retracted his own claim, leading to a heated argument.
The Exodus: From OpenAI to Anthropic
In early 2020, Altman asked executives to write peer reviews of each other. Brockman wrote a harsh review accusing Daniela of abusing power and using bureaucratic processes to exclude dissenters; Altman previewed it and called it "tough but fair." Daniela rebutted point by point, and the argument escalated until Brockman offered to withdraw his comments. By late 2020, the core team around Dario decided to leave; Daniela led negotiations with lawyers. Altman personally visited Dario's home to persuade him to stay. Dario offered to stay only if he reported directly to the board and made clear he could not work with Brockman. Before leaving, he wrote a long memo dividing AI companies into "market-oriented" and "public-interest" categories, arguing the ideal split was 75% public interest, 25% market. Weeks later, Dario, Daniela, and nearly a dozen employees left OpenAI to found Anthropic.
Today, both companies are valued at over $300 billion and are racing to go public first. At the New Delhi AI Summit in February, when Indian Prime Minister Narendra Modi and tech leaders raised their hands for a group photo, Amodei and Altman chose not to participate—they awkwardly brushed elbows instead.