This idea was originally meant for my educational online store, Level 3/4, Topics Wars & Geopolitics.
A planet where every country is given one “nuclear weapon” (or some magical equivalent of it) and a button they can press to activate it. Exactly one, no more and no less.
It’s also completely forbidden to develop weapons in any way besides that.
Why? Because of the “standoff”-effect -> because EVERYONE has that button, pressing it means mutually assured destruction, which they hope is enough to prevent anyone from ever actually using it and achieving world peace.
“It turns out that achieving world peace was easy! Keeping it, however, was … much harder.”