Washington can take several concrete steps to extend Israel's clock and exhaust diplomacy and sanctions before resorting to force.
Obama administration officials have made it clear that they believe there is still time and space for diplomatic efforts to succeed in stopping Iran from achieving a nuclear weapons capability. But Israel's deputy foreign minister, Danny Ayalon, has said it is time to declare that "diplomacy has failed."
While Israel's prime minister, Benjamin Netanyahu, has not yet declared the failure of diplomacy, he has spoken about its inability to alter the course of Iran's nuclear program. In addition, he has told his cabinet that the nuclear threat from Iran dwarfs all the other threats Israel faces and pointedly added, "Iran cannot be allowed to have nuclear weapons."
The words of Israeli leaders are signaling not just increasing impatience with the pace of diplomacy but also Israel's growing readiness to act militarily on its own against Iranian nuclear facilities.
Although the United States and Israel share the same objective of preventing Iran from acquiring nuclear weapons capability, the two differ on the point at which it may become necessary to act militarily to forestall the Iranian nuclear advance. I say "forestall" because neither America nor Israel can fully destroy the Iranian capability to build a nuclear weapon. Each country could set Iran back militarily, but neither could destroy Iran's skill or technical and engineering capacity to develop nuclear weapons. Since 2007, when Iran mastered the full nuclear fuel cycle and the means to enrich uranium on its own, it has been too late for that.
Their differences on the possible timing of military action are a function of both capabilities and perspective. The United States has significantly greater military might than Israel and therefore feels that it can wait substantially longer than Israel before resorting to force.
Israel is less patient. As Israeli Defense Minister Ehud Barak has said, Iran is rapidly approaching the moment when the depth, breadth and hardening of its multiple nuclear facilities would produce a "zone of immunity" in which an Israeli military strike would lose its effectiveness. Mr. Barak believes that Israel must act before that moment.
But the issue for the United States is not only about military capacity. It is also about having a strategy for the aftermath of any strike on Iran. Because force could not destroy Iran's nuclear capability, military action must be seen as a means and not an end. And it must be employed in a way that would contribute to the objective of setting back the Iranian nuclear program so that Iran is both less able and less willing to reconstitute it. At a minimum, that would require keeping Iran isolated and under severe economic sanctions after its nuclear facilities had been attacked.
Israel surely recognizes the importance of having a post-strike strategy that could succeed in keeping Iran isolated. But, perhaps because Israeli leaders find it difficult to surrender the military option while still facing what they perceive as an existential threat, they tend to believe that Tehran's behavior will produce a unified international position against Iran, even after a military strike.
In the words of one senior Israeli official: "The sanctions regime may be hurt for a time, but afterward it will recover, as will the diplomatic pressure on Iran, as will the intelligence battle against Iran. This is because the basic interests of the international community regarding Iran will not change."
The perspective of the Obama administration is different. From its standpoint, the isolation of Iran did not just happen on its own. It took considerable effort to persuade and mobilize the international community to impose crippling sanctions.
For the United States, this context matters. America thinks in terms of shaping an international environment so that if force becomes necessary it can be justified because diplomacy has been demonstrably exhausted and Iran, by stubbornly refusing to alter its nuclear program, will appear to have essentially brought war on itself. Preserving Iran's isolation in the event of a military strike will require denying Iran the ability to present itself as the victim.
In other words, before a military strike, it is essential to demonstrate that Iran was not prepared to accept a civil nuclear power capability with the kind of limitations that would prevent it from being able to produce nuclear weapons on short notice.
Israeli leaders wouldn't dispute the desirability of showing that diplomacy -- and the use of crippling sanctions -- had failed to change Iran's behavior. But Israelis clearly fear that their clock will run out on them and that Israel, in the words of that senior official, "will no longer be a player at that point."
The key questions for policy makers in Washington today are whether there is a way to extend the clock from an Israeli standpoint and whether it is possible to synchronize the American and Israeli clocks so that we really can exhaust diplomacy and sanctions before resorting to force. Four actions by the United States could make this possible.
First, the United States must put an endgame proposal on the table that would allow Iran to have civil nuclear power but with restrictions that would preclude it from having a breakout nuclear capability -- the ability to weaponize its nuclear program rapidly at a time of Tehran's choosing. Making such a proposal would clarify whether a genuine deal was possible and would convey to Israel that the American approach to negotiations was not open-ended.
Second, America should begin discussions with the permanent members of the United Nations Security Council and Germany (the so called P5+1) about a "day after" strategy in the event that diplomacy fails and force is used. This would signal to both Israel and Iran that we mean what we say about all options being on the table.
Third, senior American officials should ask Israeli leaders if there are military capabilities we could provide them with -- like additional bunker-busting bombs, tankers for refueling aircraft and targeting information -- that would extend the clock for them.
And finally, the White House should ask Mr. Netanyahu what sort of support he would need from the United States if he chose to use force -- for example, resupply of weapons, munitions, spare parts, military and diplomatic backing, and help in terms of dealing with unexpected contingencies. The United States should be prepared to make firm commitments in all these areas now in return for Israel's agreement to postpone any attack until next year -- a delay that could be used to exhaust diplomatic options and lay the groundwork for military action if diplomacy failed.
Although some may argue that these actions will make a military strike more likely next year, they are almost certainly needed now in order to give Israel's leaders a reason to wait.
Dennis Ross is counselor at The Washington Institute and former special assistant to President Obama for the Middle East and South Asia.