I'm not 100% certain, but I believe that option #2 of the nuclear weapons part of the Government Scenarios page has a penalty of some sort. Negative environment or happiness, I think. If lead reduces environment penalties for owning nuclear weapons by 50%, shouldn't it do the same for nations who have a Uranium trade but don't have nukes?
A minor detail, I know; but it seems logical to me.
Thanks for your input...
-LK