The prevailing view among experts seems to be that there is a strong likelihood of an Israeli attack on Iran's nuclear installations. This may be the only point on which the opponents and proponents of that move agree. But the consensus is questionable.
True, Israeli Prime Minister Netanyahu says that he won't wait for definitive proof that Iran's nuclear program is aimed at bomb building before deciding to strike, adding that the American and Israeli clocks are not in sync on this matter. But this rhetorical flourish amounts to an admission that Netanyahu couldn't get Obama's unconditional support during their recent meeting, despite his efforts to influence the President by campaigning for public and Congressional solidarity. Nor was the Prime Minister mollified by the President's statement that the United States will not allow Iran to acquire nuclear weapons and that military option is not "off the table."
But applying Netanyahu's standard would entail waging preventive war, which is altogether different from a preemptive one. The Israeli government would be claiming the right to attack based not an evident and compelling threat from Iran but on its assessment that Iran might acquire the wherewithal to harm Israel at some undefined juncture. That's an extremely permissive justification, one that few countries, even those well disposed toward Israel, will endorse, not least because Israel itself has nuclear weapons and thus a deterrent. While it's hard to imagine a U.S. president reproaching Israel, Netanyahu shouldn't bet that Obama would order American forces to join in. As for the reaction elsewhere, it will range from tepid support (at best) to condemnation, with the latter being the predominant one.
The Arab Spring has increased Israel's isolation in its neighborhood, and bombing Iran will make matters far worse. It's said that several Sunni Arab states fear the prospect of an Iran wielding nuclear weapons. Saudi Arabia and the Persian Gulf sheikdoms are most often mentioned, but so is Egypt. But no matter what the leaders of these countries might think, or communicate subtly to Washington or Tel Aviv, none will stand up and approve an Israeli attack for fear of a backlash from "the street," particularly after the mass protests of the Arab Spring. Nor will Israel find support elsewhere in the Muslim world. Take Turkey, for instance. Ankara believes that a nuclear-armed Iran would make the Middle East an even more dangerous place. The Turks nevertheless insist that the evidence on Tehran's intentions remains inconclusive; that Iran is, in any event, not close to manufacturing a bomb; and that diplomacy, not sanctions, let alone force, is the best solution.
Then there's Israeli public opinion. If you've assumed that Netanyahu's bellicosity has deep support among Israelis, you are not alone. Yet the reality is different. A recent poll shows that only 19 percent of Israelis support an attack without American support and that only 43 percent favor proceeding without it. Only 28 percent expect America to join an Israel strike, 39 percent anticipate only political support, while a third believes that Washington would stay neutral or even punish Israel. The vast majority does not think that an attack would delay an Iranian nuclear weapons program for more than five years, and a third opines that it will either accelerate it or make no difference. Similarly, prominent Israelis (including two former heads of the Mossad, Ephraim Halevy and Meir Dagan, and a former Chief of Staff of the Israeli Defense Forces, Amnon Lipkin-Shahak) have declared that an attack on Iran is unnecessary to safeguard Israel and would indeed be counterproductive. Now, Netanyahu could ignore polls and pundits, but, like all politicians in democracies, he cares for votes and cannot dismiss the electoral consequences of a decision, the ripple effects of which leave Israelis more vulnerable.
The operational obstacles that Israel will confront in executing a successful attack -- whatever that means -- have received much attention: the distance Israeli jets will have to fly (1,861 miles to and fro); the need to refuel them en route, using aerial tankers; the size of the strike force that will be needed to overcome Iran's substantial air defense network; and Iran's dispersal of its nuclear facilities, some of which are deep underground and reinforced so as to protect them against even America's most powerful bunker-busting bomb, the 30,000 lb. GBU-57 A/B "Massive Ordnance Penetrator," which Israel lacks.
While these are important, the bigger problem is strategic rather than operational. An Israeli strike would likely guarantee that Iran makes a determined and explicit bid to build nuclear weapons because its leaders will conclude that Israel would never have struck if Iran had them. That assessment will have wide support in Iran, even among those who dislike the current regime. It would be strategically obtuse to attack Iran knowing this, and there's no reason to assume that Netanyahu doesn't know it.
Moreover, Israel leaders have been sending continual warnings intended to sway Iran's leaders (insisting, nevertheless, that they are irrational and hence immune to nuclear deterrence) -- an odd thing to do if Netanyahu is counting on maximizing surprise and effectiveness.
An Israeli attack on Iran will have consequences that are multiple, prolonged, and pernicious. But it's hardly a foregone conclusion that it will occur; indeed, it's less likely than generally assumed.