PauseAI and StopAI: Inside the Anti-AI Activist Groups

PauseAI and StopAI are two anti-AI activist groups trying to slow or stop advanced artificial intelligence. They share the same fear. But they split hard over tactics. PauseAI protests within the law. StopAI breaks it. This page explains both groups, their leaders Holly Elmore and Sam Kirchner, and the events that pulled them apart.

What Is PauseAI?

PauseAI is a grassroots group that wants a temporary, global pause on training the most powerful AI systems. It does not want to ban AI forever. It wants a timeout until safety catches up.

PauseAI was founded in May 2023 in Utrecht, Netherlands. Software entrepreneur Joep Meindertsma started it. He put his job as a software CEO on hold to lead the group, according to Fortune.

The name came from an open letter. In March 2023, the Future of Life Institute urged a pause on giant AI experiments. Meindertsma took that idea and built a movement, according to Transformer News.

A legal, global movement

PauseAI now has local chapters across many countries. In May 2024, it staged protests in thirteen countries before the AI Seoul Summit. The group insists on peaceful, lawful protest.

PauseAI often coordinates with police and site security before a demonstration. That commitment to legality would later become the wedge that divided the movement.

The group's demands are also aimed at governments, not just companies. PauseAI argues that no single lab can pause on its own without losing the race. So it presses for binding international rules that would force everyone to slow down at once.

What Is StopAI?

StopAI is an activist group that wants a permanent, worldwide ban on building artificial general intelligence. A pause is not enough for StopAI. It wants a full stop.

StopAI was founded in 2024 by Sam Kirchner and Guido Reichstadter. Both men had previously worked with PauseAI, according to Transformer News.

StopAI argues that superhuman AI is inherently uncontrollable. So no company should be allowed to build it. The group frames its cause in stark, existential terms.

Civil disobedience at its core

StopAI is best known for civil disobedience. Its members have blocked doors, chained themselves to gates, and been arrested. The group calls itself a nonviolent civil resistance organization, according to KQED.

StopAI is based in the San Francisco Bay Area. It has staged repeated protests outside OpenAI, the maker of ChatGPT. For the wider movement, see our who is fighting AI guide.

Who Is Holly Elmore?

Holly Elmore is the leader of PauseAI US and one of the most prominent voices for pausing AI. She is the public face of the group in the United States.

Elmore is based in Berkeley, California. She holds a PhD in evolutionary biology from Harvard, according to Fortune. Before her activism, she worked at a think tank focused on animal welfare.

Elmore and Meindertsma met on Slack. They discovered they had each named their own idea 'Pause AI.' Both had drawn inspiration from the Future of Life Institute letter, according to Fortune.

Rooted in effective altruism

Elmore came up through the effective altruism community. That movement asks how to do the most good with limited resources. Read more on our effective altruism explainer.

Elmore argues that public pressure can still change AI's path. She favors visible, lawful protest over backroom lobbying. That approach put her on a collision course with StopAI.

Who Is Sam Kirchner?

Sam Kirchner is a co-founder of StopAI and was, for years, its most visible activist. He led the group's public face until late 2025.

Kirchner, reported to be 27, launched StopAI in 2024 with Guido Reichstadter, according to the San Francisco Standard. He led monthly protests outside OpenAI's San Francisco offices.

Kirchner became known for dramatic stunts. He chained himself to OpenAI's gates. He was arrested for blockading the company's doors, according to the San Francisco Standard.

From protest to crisis

Kirchner's activism later took a darker turn. In late 2025 he vanished amid a reported mental health crisis. We cover that story in detail below.

Civil Disobedience: Blockades and a Subpoena

StopAI's signature tactic is physically blockading OpenAI's offices, which has led to multiple arrests. The group treats the courtroom as a stage for its message.

On February 22, 2025, three StopAI protesters were arrested. They barricaded the doors of OpenAI's San Francisco offices and refused to leave, according to KQED. Guido Reichstadter and Derek Allen were among the defendants.

The activists did not deny the act. They admitted they blocked business operations at OpenAI, according to the San Francisco Gazetteer. They said the trial itself would raise awareness of their cause.

The subpoena stunt

StopAI also targeted OpenAI CEO Sam Altman directly. On November 3, 2025, a San Francisco Public Defender's Office employee served Altman a subpoena onstage, according to Futurism. Altman was speaking with Warriors coach Steve Kerr at the Sydney Goldstein Theater.

The subpoena aimed to compel Altman to testify at the activists' criminal trial. Altman's lawyers moved to throw it out. StopAI claimed responsibility on social media.

A note on the broader backlash

These groups are one slice of a much larger reaction to AI. For the full picture of the movement and how to engage with it, see our fighting back hub.

The Split Between PauseAI and StopAI

PauseAI and StopAI split because PauseAI refused to break the law and StopAI insisted on it. That single disagreement created two separate organizations.

Kirchner and Reichstadter started inside PauseAI. But PauseAI leadership would not allow illegal direct action, like chaining themselves to OpenAI's doors, according to Transformer News.

So the pair left and founded StopAI in 2024. Holly Elmore was blunt about the break. 'I kicked them out,' she told Fortune.

Two philosophies

The split reflects a deep divide among the AI doomers. One side lobbies and protests strictly within the law. The other embraces civil disobedience and accepts arrest.

Both groups say they reject violence. But they disagree on how far protest should go. That question grew far more serious in the events that followed.

The Disappearance of Sam Kirchner

Sam Kirchner disappeared on November 21, 2025, after allegedly threatening violence against OpenAI staff. His whereabouts remained unknown in later reporting.

According to the San Francisco Standard, Kirchner was in a mental health crisis. Callers told police he had threatened to go to OpenAI offices and 'murder people.' OpenAI locked down its San Francisco offices in response.

StopAI said Kirchner had assaulted a member who refused to let him buy a weapon with group funds. The group blocked his access to the money, warned police, and expelled him, according to the San Francisco Standard.

A bench warrant and a search

Kirchner failed to appear at a court hearing that same day. A judge issued a bench warrant for his arrest, according to KQED. Police had not located him as of later reporting.

He reportedly left his laptop and phone behind. He took a bicycle and camping gear, according to the San Francisco Standard. City Journal framed the case as a warning about radicalization.

The fallout

StopAI members said they were rethinking their strategy after Kirchner vanished, according to the Daily Californian. The criminal trial of the remaining defendants was delayed. The story remains a sober reminder that activism and personal crisis can dangerously overlap.

PauseAI vs StopAI: How They Compare

PauseAI and StopAI differ most in their goals and their willingness to break the law. The table below lays out the key contrasts side by side.

The bottom line

PauseAI and StopAI show how far the anti-AI backlash has traveled. One group lobbies. One group blockades. Their story is now tangled with a missing person and real fears of violence.

The line between passionate protest and dangerous extremism can be thin. Reporting these facts soberly matters. To keep up with the latest, follow our daily AI briefing.