More than 700 public figures from Prince Harry to Steve Bannon signed an open letter released Wednesday calling for a prohibition on developing superintelligent artificial intelligence until safety measures are established and the public supports such technology.

The letter, coordinated by the Future of Life Institute, represents one of the most diverse coalitions yet assembled around AI regulation concerns.

Signatories include five Nobel Prize laureates, Apple co-founder Steve Wozniak, British billionaire Richard Branson, and former Joint Chiefs Chairman Mike Mullen alongside entertainment figures like Joseph Gordon-Levitt and musician will.i.am

Unprecedented Coalition Crosses Political Divides

The 30-word statement declares: "We call for a prohibition on the development of superintelligence, not lifted before there is broad scientific consensus that it will be done safely and controllably, and strong public buy-in".

The letter unites an unlikely political spectrum, from Prince Harry and Democratic foreign policy expert Susan Rice to conservative commentators Steve Bannon and Glenn Beck.

This bipartisan approach reflects the Future of Life Institute's strategy to engage President Donald Trump's administration, even as the White House has sought to reduce AI development restrictions.

Prince Harry emphasized the stakes in his accompanying message: "The future of AI should serve humanity, not replace it. I believe the true test of progress will be not how fast we move, but how wisely we steer. There is no second chance".

Tech industry silence as AI race intensifies

Notably absent from the signatories are the CEOs of major AI companies racing toward superintelligence. OpenAI's Sam Altman, Google's Demis Hassabis, and Meta's Mark Zuckerberg did not sign, despite previous participation in AI safety discussions. Only one current OpenAI employee, technical staff member Leo Gao, added his name to the letter.

The letter targets tech giants like Google, OpenAI, and Meta that are "racing each other to build a form of artificial intelligence designed to surpass humans at many tasks". Recent polling released alongside the letter showed 64% of Americans believe superintelligence shouldn't be developed until proven safe, while only 5% support rapid development.

Max Tegmark, Future of Life Institute president and MIT professor, acknowledged the competitive pressures facing AI companies. "I really empathize for them, frankly, because they're so stuck in this race to the bottom that they just feel an irresistible pressure to keep going and not get overtaken by the other guy," he said.

This marks the institute's second major AI letter since 2023, when a previous call for a six-month pause on advanced AI development gained over 1,000 signatures but failed to slow the industry's pace.