First, is it even possible?
The answer is yes, absolutely. There is enough (non-weapons grade) spent civilian nuclear reactor fuel to get enough radioactive materials. Much more importantly, there is plenty of “know how” amongst Ukrainian scientists and engineers. Besides, bringing in radioactive materials or specialists is something the AngloZionist Hegemony could do. Did I mention plenty of starry-eyed Ukronazi politicians daydreaming on camera about how to nuke Russia and kill as many Russians as possible?
https://thesaker.is/a-few-thoughts-about-the-dirty-bomb-thesis-and-the-role-of-hatred/
Maybe this is the specific reason why Israel is last as is mentioned in the Q drops.
Could they be the ones essentially holding us hostage due to the threatened use of suitcase nukes?
Yes, it even has a name - it's the Samson option.
Here is the toned down wiki entry. https://en.wikipedia.org/wiki/Samson_Option
I think the real thing would be devices already in place in American cities. You know they would do it.