It seems to me that to a degree nuclear weapons show some of the problems with a research ban. I think that it's possible that nuclear weapons are proliferating just very slowly. The problem seems to be that once someone engages in forbidden research, then their rivals feel the need to as well. E.g. we allowed China to get a nuclear weapon so India decided they needed one which led to Pakistan needing one. More currently, we allowed Israel to get nuclear weapons so now Iran is likely trying to get them.

It's also notable that the two instances where people gave up nuclear weapons, Gaddafi and Ukraine; have both ended poorly for the people who gave them up.

All this to say, I wonder if it might be possible to slow research on a subject but not to stop it completely.