(3 of 4)
It's unclear how effective any air force will be against the main targets. The massive enrichment facility at Natanz may be vulnerable to Israel's bunker busters, even six stories underground. But Iran this month announced that centrifuges are spinning in the new Fordow facility outside Qum, which is thought to be protected by a shelf of rock more than 260 ft. (80 m) thick. That may be beyond the reach even of the Massive Ordnance Penetrator, a 30,000-lb. (13,600 kg) bomb built for the U.S. Air Force and delivered in recent weeks to B-2 stealth bombers newly modified to carry it.
Plus, getting the necessary ordnance over the targets isn't easily done. "The Israelis just don't have the reach to launch a sustained campaign," says Tim Ripley, a Middle East defense analyst for Jane's Defence Weekly. In "Mission Improbable," his report assessing the prospects of an Israeli strike, Ripley notes that Israel lacks aircraft carriers or other forward bases to shorten the distance to Iran. Which means that in order to reach targets more than 1,000 miles away, Israel must rely on aerial-tanker planes to refuel scores of fighters en route, on the way back or even in both directions should pilots find themselves doing a lot of maneuvering. And Israel has only a handful of such flying filling stations. "The Israelis have loads of fighters," says Ripley. "But it's not quite like the U.S. Air Force, which has got hundreds of tankers."
The sheer number of targets makes any strike even more daunting, says Yiftah Shapir, a former Israeli Air Force intelligence officer whose duties involved planning for such strikes. "What you really have to calculate is not targets but aiming points," says Shapir, now an analyst at the Institute for National Security Studies in Tel Aviv. "Each target has numerous aiming points." Shapir tells TIME, "A strike could be done, but it could never do the damage we did to Osirak, where Osirak was all they had."
Cordesman reckons Israel probably has enough aircraft and enough range to do serious damage to 10 to 12 of Iran's atomic facilities. But damaged labs can be rebuilt, he notes, and Iran has announced plans for 10 new enrichment sites--further dispersing later-generation centrifuges in places smaller, harder to locate and easier to harden. The issue, Cordesman says, is not simply capability but consequences. "If anyone tells you this is sort of binary, either 'Yeah, they can do it' or 'Oh, no, they can't,' they don't know what they're talking about," he says. "Israel is going to act strategically. It's going to look at the political outcome of what it says and does, not simply measure this in terms of some computer game and what the immediate tactical impact is."
One forgotten lesson of Osirak is that, as a consequence, Saddam Hussein took his nuclear weapons program into the shadows and got much closer to a bomb before the rest of the world caught wind of his intentions. An attack on Iran, even one led by the U.S., might produce only a temporary halt in its nuclear program--and a greater resolve to develop weapons out of sight of international inspectors, if only to buttress Iranian security in years to come.