I said yesterday that I thought Israel might be preparing to attack Iran if it felt that the Geneva agreement wasn't having the desired effect (which, in my opinion, it won't). Now Foreign Policy has a very interesting look at the possible use of nuclear weapons by Israel against Iran. Here's an excerpt.
The recognition of Israel's nuclear capabilities will continue to matter over the next six months because, if we are to take Tel Aviv seriously, Israel could undertake a unilateral military attack against Iran's known nuclear facilities. Should the IAEA's outstanding questions about the possible military dimensions of Iran's nuclear program go unaddressed, or access to sensitive sites remain restricted, there are intentionally ambiguous undefined conditions under which Israel might attack Iran, with or without the United States. For example, Iran's Fordow Fuel Enrichment Plant could be one target of an Israeli nuclear weapon. Fordow is a uranium-enrichment facility located beneath 60 to 80 meters of granite near the city of Qom. The facility at Fordow, according to Iran's declaration to the International Atomic Energy Agency, is designed to contain up to 2,976 IR-1 centrifuges in 16 cascades. The Institute for Science and International Security has estimated that this set-up could produce one bomb's worth -- or "significant quantity" -- of highly enriched uranium per year.
In August, Yuval Steinitz, Israel's minister for international affairs, strategy, and intelligence, claimed that Iran's uranium-enrichment facilities can be "destroyed with brute force," which he described as "a few hours of airstrikes, no more." Yaakov Amidror, who recently stepped down as national security advisor, asserted this month that Israel can "stop the Iranians for a very long time." Asked whether this includes Iran's deeply buried nuclear installations, he responded, "including everything."
Most U.S. government and nongovernmental experts in weaponeering effects disagree with Amidror. They have concluded that Israel's conventional air-dropped bombs cannot penetrate the bedrock to reliably destroy the centrifuges located within Fordow. Moreover, both George W. Bush's and Barack Obama's administrations have refused to provide Israel with the Pentagon's largest (and recently further improved) conventional bunker-buster bomb, the Massive Ordnance Penetrator. Respected defense reporter David Fulghum quoted an anonymous U.S. defense specialist as saying, "Right now the Israeli capability against deeply buried targets is not much more than a noise-level effect." Given Israel's inability to deliver what one U.S. official termed "a knockout blow" against well-defended nuclear sites like Fordow with conventional bombs, a low-yield nuclear weapon could be the only viable alternative for a unilateral Israeli strike.
There's more at the link. Interesting reading.
I have no doubt that if Israel felt terminally threatened by Iran (or anyone else), she would use nuclear weapons against them without hesitation. Look up Masada and the Holocaust to understand why.