You are missing several factors. Just 1:
If Iran detonates two suitcase nukes in Israel, that will not significantly affect Israel’s capacity to nuke Iran - and Israel WILL then turn Iran into a glass sheet. I doubt Iran will even have time to announce their follow up “threat”.
The Iranian mullahs are “crazy”, but, most of the present leadership is not THAT crazy.
Substitute a nuked up SA for Israel, and the suitcase bomb strategy is even weaker. (And in the shorter term you are more likely focusing on, SA will just turn to the Paks.)
I’m not saying the suitcase bomb strategy is impossible, but I think it is far less likely than the inevitable results of a nuclear arms race in the ME.
Either way, we CANNOT allow Iran to get nukes, and that’s what this is all about.
We're in total agreement on the above comment.