Israel would be hard-pressed to destroy all of Iran's best-known targets. What's more, Iran has had years in which to build up covert facilities, disperse elements of its nuclear and missile programs, and develop options for recovering from such an attack.
Israel has fighters, refueling tankers and precision-guided air-to-ground weapons to strike at all of these targets—even if it flies the long-distance routes needed to avoid the most critical air defenses in neighboring Arab states. It is also far from clear that any Arab air force would risk engaging Israeli fighters. Syria, after all, did not attempt to engage Israeli fighters when they attacked the reactor being built in Syria.
In August 2003, the Israeli Air Force demonstrated the strategic capability to strike far-off targets such as Iran by flying three F-15 jets to Poland, 1,600 nautical miles away. Israel can launch and refuel two to three full squadrons of combat aircraft for a single set of strikes against Iran, and provide suitable refueling. Israel could also provide fighter escorts and has considerable electronic-warfare capability to suppress Iran's aging air defenses. It might take losses to Iran's fighters and surface-to-air missiles, but such losses would probably be limited.
Israel would, however, still face two critical problems. The first would be whether it can destroy a hardened underground facility like Natanz. The second is that a truly successful strike might have to hit far more targets over a much larger area than the three best-known sites. Iran has had years to build up covert and dispersed facilities, and is known to have dozens of other facilities associated with some aspect of its nuclear programs. Moreover, Israel would have to successfully strike at dozens of additional targets to do substantial damage to another key Iranian threat: its long-range missiles.
At best, such action would delay Iran's nuclear buildup. It is more likely to provoke the country into accelerating its plans. Either way, Israel would have to contend with the fact that it has consistently had a "red light" from the Obama administrations opposing such strikes. Any strike that overflew Arab territory or attacked a fellow Islamic state would stir the ire of neighboring Arab states, as well as Russia, China and several European states.
Israel has enough strike-attack aircraft and fighters in inventory to carry out a series of restrikes if Iran persisted in rebuilding, but it could not refuel a large-enough force, or provide enough intelligence and electronic warfare capabilities, to keep striking Iran at anything like the necessary scale. Moreover, Israel does not have enough forces to carry out a series of restrikes if Iran persisted in creating and rebuilding new facilities, and Arab states could not repeatedly standby and let Israel penetrate their air space. Israel might also have to deal with a Russia that would be far more willing to sell Iran advanced fighters and surface-to-air missiles if Israel attacked the Russian-built reactor at Bushehr.
Any Israeli attack on an Iranian nuclear target would be a very complex operation in which a relatively large number of attack aircraft and support aircraft would participate. The conclusion is that Israel could attack only a few Iranian targets—not as part of a sustainable operation over time, but as a one-time surprise operation.
The alternatives, however, are not good for Israel, the U.S., Iran's neighbors or Arab neighbors. Of course being attacked is not good for Iran. Israel could still strike, if only to try to buy a few added years of time. Iranian persistence in developing nuclear weapons could push the U.S. into launching its own strike on Iran—although either an Israeli or U.S. strike might be used by Iran's hardliners to justify an all-out nuclear arms race. Further, it is far from clear that friendly Arab Gulf states would allow the U.S. to use bases on their soil for the kind of massive strike and follow-on restrikes that the U.S. would need to suppress Iran's efforts on a lasting basis.
These problems are why a number of senior Israeli intelligence experts and military officers feel that Israel should not strike Iran, although few would recommend that Israel avoid using the threat of such strikes to help U.S. and other diplomatic efforts to persuade Iran to halt.