Exactly what many in the Persian government want - worldwide cataclysm, thus summoning the Twelfth Imam out from whatever well he's napping in, and Islam ruling the world.
Nonsense.
While many may subscribe to this gibberish, even the Mad Mullah’s from Persia understand that what will be unleashed could quite possibly end with the annihilation of most life on the planet. The Middle East will burn first and foremost and more likely than not nothing in that area will survive.
There won’t be a world for Islam to rule, not to mention there won’t be an Islam if they push it too far. They know this, and anyone who isn’t kidding themselves knows this as well.
I couldn’t think of a better reason to permanently remove Islam from the planet than to do what you seem to believe they are eager to do. The rest of the world, or what’s left of it, would likely decide to eradicate Islam and all Muslims and not stop until such a goal was accomplished.
Iranians know this. They talk a good game and play footsie behind the scenes (along with stirring up as much trouble as they possibly can to further their agenda), but to push the nuclear button outside of the Middle East is a whole different level of suicide. Even pushing the button in the ME would be a risk that they may or may not be prepared to take, but it looks like we’ll find out sooner or later at this rate.
It's easy to dismiss insane ideas. But real people hold insane ideas.
For example, Hans Hoerbiger's "World Ice Theory" was the official cosmology of the Nazi Party.
“Exactly what many in the Persian government want - worldwide cataclysm, thus summoning the Twelfth Imam out from whatever well he’s napping in, and Islam ruling the world.”
Mix and match
The goal of Sunni Islam is to rule the world. The goal of Shia Persian Twelvers (government) Islam is to bring eveyone to Paradise - aka the extinction of the human race.