Still, you don't address the issue of
A)Where they'll come up with a nuclear bomb,
B)Where or how they'll hide it on our soil,
C)How they'll maintain it,
D)How they'll deliver it.
Everything else is just speculation based on theory, not evidence.
Hope you have sun screen. Nukes are not that hard to get your hands on if you are pals with N. Korea. They can easily be driven across the border via eighteen wheeler, which BTW drive across the desert to a main highway every night from Mexico.
They don't have to be maintained, they can be driven to any and every major city, or destination of their choice and detonated.
It's not that hard to do. Before 9-11 you would have been protesting the likelihood of multiple terrorists taking over multiple commercial airliners and crashing them in New York and D.C. How smart is it to underestimate a determined enemy?
Our borders are joke enough that getting just about anything across would be easy enough for the determined. It is possible the "evidence" is there, just as the "evidence" for what what became 9/11 was there.