Imagine how differently history would have gone if the half-dozen or so people who figured out nuclear fission didn't go running to their politicians to loudly announce "look, we've discovered an amazing new type of weapon", but instead kept quiet and never talked about it.

I wonder this was Gödel's thinking when he was sent from Europe to America to relay the secret of the A-bomb, and instead he stayed silent [0]. Perhaps he anticipated, like a silent prisoners' dilemma, that the other half-dozen would also stay quiet, and then nuclear weapons would never appear.

[0] https://news.ycombinator.com/item?id=40378904 ("The spy who flunked it: Kurt Gödel's forgotten part in the atom-bomb story (nature.com)")

(Maybe there's a colorable argument the world's nations should agree not build any very large particle accelerators, on the off chance they accidentally discover a new type of world-ending physics weapon. Given the pricetags of frontier-size colliders, it'd be possible to keep this particular genie locked in its bottle almost indefinitely).