The Davy Crockett is one of the most scary devices ever made. You could smuggle that thing into just about anywhere with relatively little chance of detection. I assume they kept good track of where those ended up, that's as close to a suitcase nuke as there ever existed (as far as I know). That's a proliferation nightmare and the only good thing about it is probably that it's very hard to make a small nuke work reliably.