Yes, the U235 and Pu239 would still work. But the firing circuits, batteries, etc. very well might not.

However -- complicated circuitry isn't necessary. Just have a fanatic slam two subcritical masses together as fast as possible. The result will be low yield (perhaps in the 0.5 to 0.8 KT range) and very, very "dirty." Neither of which will matter to the dead....

There are other scenarios too, and I will NOT go into them.

A nuclear explosion in or near some US city, probably within the next ten years, would not surprise me at all.