> Nation states, sure, they've probably bought a few […] If a nation state has a nuke, it's in their interest to hold it as deterrent.

It also is in their interest to let ‘them’ know they have an atomic bomb. Of course, they could have done that secretly, but I think the world at large would know of it, anyways. Since that hasn’t happened (Pakistan and North Korea built their own devices, and so, likely, did Israel, all after buying it stealing the technology), I think it’s unlikely this happened.

> If they [terrorists] use it, they achieve the attention and blood they seek, while the world doesn't know where they all live

Terrorists don’t want to instill fear, they want to instill fear in the pursuit of political aims. Because of that, they would have to tell the world they were responsible. I think the world would figure out where they live from that.

I agree with you that it’s unlikely terrorist groups are in possession of nuclear devices. It’s not a weapon that’s easily hidden (its radiation probably gives it away), and it’s expensive to obtain, and they wouldn’t have many, so losing one without using it would be a big loss.

Their size (you probably need a truck to move them) is more of a challenge. Nuclear weapons are well-shielded to not make handling them dangerous, therefore their radiation is barely noticeable. After all, that's the reason lost ones are so hard to locate. Put them in a metal crate or a container, and they should fade into the natural background radiation.

I don’t know about any shielding. They’re just plutonium and uranium, which aren’t very radioactive. They wouldn’t needlessly add weight to the weapon.

Is it thought that any of these lost wepons were an off the books way to provide non nuclear allies with a deterrent.

I don’t think that’s the case. Secretly having a bomb gives you the ability to strike hard, but on its own it doesn’t deter.

If you want to deter, it’s not sufficient to have teeth, you have to show them or at least convince your enemy to believe you have them, and that only seems to be happening by countries that built their own such as Russia, North Korea and Pakistan.

So, how would, say, Canada secretly having a bomb deter anybody from attacking it?

Also, the USA already provides non-nuclear allies with a way to deter by storing on-the-book weapons in their countries (https://en.wikipedia.org/wiki/Nuclear_sharing) That doesn’t have to happen off the books.

Are you suggesting there are countries they trust enough to store nuclear bombs there, while they don’t want the world at large to know about that? I can’t think of any country that would qualify for that.

I was thinking about somewhere like Israel or Taiwan, that a sitting president might be willing to push the button to defend a nation, but not have confidence that their successor would do the same, and so put the matter in the hands of the nation itself.

Another possibility: intelligence agency has an unaccounted for nuclear weapon, particularly one made by another country, and holds onto it secretly in case they ever want to commit a false-flag terrorist attack with it. Such a bomb needn't be fully operational; a failed detonation might still achieve the desired effect.

I like this. How has a thriller not be made about this very scenario?

I may be misremembering, but I think this was the plot of a Tom Clancy novel.

Yep, Tom Clancy's Sum of All Fears has a very similar premise. Israel loses a nuclear bomb during the Yom Kippur War, which is subsequently recovered by Palestinians who team up with some East Germans to start a war between America and the Soviet Union by blowing up Denver (the bomb fizzles.)

How did they screw the movie up so very thoroughly? The novel was not Clancy's best, but still great, very readable. I found the movie unwatchable.

Yeah I agree. Clancy movie adaptations seem to have all been downhill since Hunt for Red October. Arguably his books too, although Red Storm Rising is still my favorite (and probably impossible to make a good movie of, the scope is too large and Russia too competent.)

I've long thought Red Storm Rising could have made a really good miniseries. You're right the scope is too big for a singular movie but maybe just right for a 6-10 hour series. It won't happen now though given Russia's recent displays of competence. The premise will be considered too outlandish. It would end up as believable as the Red Dawn remake or the one where the North Koreans shoot up the White House.