At any rate, that's not what Ahmadinejad said.
"President Mahmoud Ahmadinejad did quote Ayatollah Khomeini to the effect that "this Occupation regime over Jerusalem must vanish from the page of time" (in rezhim-e eshghalgar-i Qods bayad as safheh-e ruzgar mahv shavad). This was not a pledge to roll tanks and invade or to launch missiles, however. It is the expression of a hope that the regime will collapse, just as the Soviet Union did. It is not a threat to kill anyone at all."
The top ten things you didn't know about Iran | Salon
Do I think he'd be sad if Israel was wiped off the map? No. I'm simply saying he never threatened to do it, and has even said Iran is no threat to Israel.
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Yes, I have been told that, on this message board. Excuse me if I don't take it all that seriously. I've also been told that they told the IAEA about this facility as they're supposed to do, and I think if it really were a threat we'd have heard about this facility long beforehand since the U.S. government has apparently been keeping it under wraps for years as well.
Using nukes on Israel would not make him the most powerful person in the Middle East, it would make him dead. Israel has nukes of its own that it would most certainly not hesitate to use in retaliation.