I read John A MacPhee's book, 'The Curve of Binding Energy', a long while back. He describes visiting nuclear plants with Ted Taylor, former Los Alamos bomb designer, and also going around the World Trade Centre, where Taylor vividly described the damage a satchel nuke could do. (It turned out, a few years later, to be be rather less than a few Saudis with box cutters and two planeloads of jet fuel could wreak.) Taylor had developed the smallest fission bombs ever made, using tritium boosting and beryllium cladding. He later became a strong proponent for increased vigilance over nuclear materials.
In New Zealand, our government in the 80s rejected the US nuclear umbrella, effectively being frozen out of the US - Australia - New Zealand ANZUS defence pact, but we had the luxury of being about one earth radius away from any potential threat. Now that America is proving an unreliable partner, it's likely that countries without their own nuclear deterrent, or with allies so armed, will rapidly develop their own. Russia's treatment of Ukraine, and Israel's of Syria (and possibly Iran), are a powerful incentive, as were the deaths of Saddam Hussein and Gaddaffi for any worried dictator. Of course they wouldn't be using reactor grade plutonium, enrichment and small dedicated weapons production reactors are the obvious approach, if even North Korea can do it.
Hopefully the rollout of civil nuclear power can proceed unaffected, as higher burnup and new reactors make diversion even more implausible.
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