Stop AI

Stop AI is a Bay Area–based grassroots organization founded in 2024 to pursue a permanent global ban on the development of artificial general intelligence and artificial superintelligence. It is the primary adopter in the American AI-opposition movement of nonviolent direct action (NVDA) as a tactical register — deliberate law-breaking, physical obstruction of AI company offices, and intentional arrest-seeking — placing it in a distinct civil-disobedience tradition within the broader landscape of AI pause and safety advocacy.

Founding and break from PauseAI

Stop AI was founded in 2024 by Sam Kirchner, a 27-year-old mechanical engineering student who had relocated to the Bay Area from Seattle after becoming convinced that superintelligence development posed an existential threat, and Guido Reichstadter, a 45-year-old jeweler with a physics and mathematics background and a prior history of climate activism. A third co-founding figure was Remmelt Ellen, a Dutch national connected to both co-founders through the PauseAI Discord community.

The break from PauseAI was tactical: PauseAI's leadership refused to authorize illegal direct actions, and Stop AI was founded specifically to pursue the forms of civil disobedience PauseAI would not sanction — chaining to doors, blocking egress, and deliberately seeking arrest to draw media attention and clog the judicial system. The two organizations share the same core demand — a halt to dangerous frontier AI development — but occupy opposite ends of the tactical spectrum within that broad demand.

Membership and structure

Stop AI assembled a loose membership of roughly 200 activists across the Bay Area. Five core organizers, including Kirchner and Reichstadter, pooled resources to rent a shared house in Oakland as the organization's operational base and de facto headquarters. The organization is structured around collective leadership and governed by Five Principles of Unity: prioritization of biological life, commitment to non-violence, democratic values, informed consent, and personal AI limitation.

Key protest actions

Stop AI's direct-action campaign concentrated on the San Francisco offices of frontier AI companies. In June 2024, approximately 50 participants rallied outside OpenAI's offices; five people sat in front of the entrance and locked the doors, resulting in the arrest of three — Reichstadter, Derek Allen, and Jacob Freeman. On February 22, 2025, the organization mounted a more elaborate blockade: Kirchner, Reichstadter, and Wynd Kaufmyn chained the front doors of OpenAI's 3rd Street headquarters shut, were arrested, and charged with trespassing, unlawful assembly, and obstructing business operations. The co-defendants openly admitted to the blockade and framed their trial as a platform to argue the necessity defense — that illegal obstruction was justified to prevent the greater harm of unchecked AGI development.

Reichstadter also staged a hunger strike outside Anthropic's headquarters in September 2025, and, in a separate action that November, a Stop AI member successfully served OpenAI CEO Sam Altman with a legal subpoena while Altman was onstage at a public event at the Sydney Goldstein Theater in San Francisco with Golden State Warriors coach Steve Kerr. In December 2025, Reichstadter was arrested again after violating a judge's order barring him from OpenAI's premises.

2025 leadership crisis

In October 2025, Stop AI held internal elections and unanimously chose Matthew Hall (known within the organization as Yakko) as its leader. The transition coincided with deteriorating conditions inside the organization: funding had dwindled, and Kirchner's tactical views had drifted toward positions the rest of the membership would not sanction. On the night of November 20–21, 2025, Kirchner allegedly assaulted Hall during an internal dispute over messaging and nonviolence, stating afterward that "the nonviolence ship has sailed for me." That morning, Kirchner posted on social media that he was no longer affiliated with Stop AI, cleared out his belongings from the Oakland house, and disappeared. He had also failed to appear at a court hearing for his February 2025 trespassing charges, resulting in a bench warrant for his arrest. OpenAI locked down its San Francisco offices after members reported concerns about Kirchner's mental state. Both Kirchner and Reichstadter were removed from the organization.

Current status

Under a new collective leadership of five coleaders — including Valerie Sizemore, Matthew Hall, and Wynd Kaufmyn — Stop AI has maintained its nonviolent civil-disobedience posture and affirmed that its "current leadership is deeply committed to nonviolence in both actions and statements". The organization participated in a local "Stop the AI Race" protest in early 2026. As of June 2026, Kaufmyn is standing trial in San Francisco — the first Stop AI member to face a full jury trial for the February 2025 OpenAI blockade — with the defense pursuing a necessity argument. The organization is in a rebuilding phase, working to strengthen internal structures after the 2025 disruption while remaining committed to civil disobedience as the primary tactical register.