A nuclear weapon has not been used since 1945, when the US Armed Forces dropped two such bombs on the Japanese cities of Hiroshima and Nagasaki during World War II. Now, according to London's Sunday Times, Israel is preparing for its own Hiroshima and has drawn up plans to not only introduce the weapon of mass destruction into the Middle East but even use it against Iran. The newspaper report, improbable as it might sound, should not be immediately dismissed. While Israel is publicly rooting for diplomatic efforts to stop Iran's nuclear program, there is no doubt that the IDF - and particularly the Air Force - are preparing for the possibility that Israel might decide to launch a military strike against the Islamic Republic's nuclear facilities. But would Israel use tactical nuclear weapons - if it had them - to do so? According to foreign reports, Israel has a large arsenal of nuclear weapons and according to the Sunday Times report, has been training with low-yield warheads that are just large enough to cause the necessary destruction at Iran's nuclear facilities, but also just small enough to contain the blast and prevent major collateral damage and fallout. While it would be difficult to completely destroy all of Iran's several dozen nuclear facilities, senior officials and IAF officers believe that a successful strike on a number of key elements of the nuclear program - such as the uranium enrichment center in Natanz, the heavy water facility at Arak and the Isfahan nuclear technology center - would be enough to stop the country's race for nuclear power. Assuming strikes on these facilities would suffice in at least temporarily stopping Iran's atomic race, there are still many hurdles along the way, some of which could potentially be passed by using tactical nuclear weapons. The Sunday Times report is not the first to raise the "tactical nuclear" possibility. Last April, Seymour M. Hersh wrote in the New Yorker magazine that the United States was considering using bunker-buster bombs tipped with nuclear warheads to strike at Iran's nuclear facilities. If Israel decided to attack Iran, in addition to the difficulty in flying directly to the country and neutralizing its air defenses, the IAF would also have to succeed in penetrating bunkers at the nuclear facilities - some known to be dozens of feet below ground and reinforced by concrete and steel. According to Israeli officials, while an air strike on Iran could be successful, the IAF would need exact intelligence on each target and on the type of bunker, its depth, and what type of reinforcements it featured. Those pieces of information are crucial for choosing the type and number of bombs the IAF would need to drop. This is where tactical nuclear weapons could conceivably come in. While bunker buster bombs would still be needed, the powerful blast of a low-yield nuke could do the trick in further penetrating and destroying the underground facility. If Israel indeed has nuclear weapons and the ability to manufacture low-yield warheads, as the Sunday Times report claims, this option would definitely be under consideration. While the use of nuclear weapons might be tempting - due to their strength - there is a downside that could in the end tilt the scales in the direction of conventional weapons. While Israel is suspected of possessing nuclear weapons, the official Israeli policy has for years been not to be the first country in the Middle East to introduce nuclear weapons into the region. In addition, Israel would be reluctant to use a WMD that could set off a regional war. If, however, Iran is Israel's greatest existential threat ever, as Prime Minister Ehud Olmert claims it is, then even the hitherto unthinkable might be considered - even tactical nukes - when it comes to Israel's survival.