The Netanyahu government, convinced that sanctions have failed and that Iran is rapidly nearing both nuclear capability and the point of invulnerability to an Israeli attack, has clearly begun preparing public opinion for a military strike. The Obama administration, preoccupied with the elections, continues to cling to sanctions, stressing that the US’s unique military capabilities will still enable it to act for some time and thus that it is too early for a strike.Technically, this is true, but Iran is just months from having sufficient fissile materials for its first bomb and if it disperses them, or actual bombs once operational, around the country, the US too will no longer have the ability to strike.The writer is a senior fellow at Harvard’s Kennedy School, and was a deputy national security adviser in Israel. He is the author of the forthcoming Zion’s Dilemmas: How Israel makes National Security Policy.President Barack Obama maintains that his policy is one of prevention, not containment, and that the US will have sufficient intelligence to know if Iran is about to cross the nuclear threshold and would act to prevent this. The record, however, is not encouraging.His predecessors, Bush and Clinton, maintained that a nuclear North Korea was unacceptable, but it went nuclear nonetheless, and US intelligence on the North Korean, Indian and Pakistani nuclear programs was insufficient. The US did not even know about Libya’s or Syria’s programs and the intelligence on Iraq proved flawed. The question is whether Obama is wisely and cautiously navigating American policy in the face of an unusually difficult threat, or lacks the courage to make historic decisions in the face of grave dangers.For Israel, no decision is more fateful.A fierce and unprecedented debate is underway in Israel about the necessity and likely consequences of an Israeli strike, between those who believe that a nuclear Iran poses a truly existential threat and thus that Israel must act, and those who believe that it is “merely” grave, and that Israel could, in extremis, live with it.As long as any viable alternatives exist, no one wishes to take military action, certainly not in the face of strong American opposition. Time, however, is running out.Prime Minister Binyamin Netanyahu and Defense Minister Ehud Barak both appear to be firmly among the existentialist camp and thus believe that Israel must act. Failing to do so and allowing Iran to go nuclear, they maintain, poses dangers to Israel that far outweigh the costs of the Iranian response and so they prefer to pay a limited, if certainly painful, price today, to forestall having to pay a far greater one in the future.The question is whether Netanyahu and Barak are courageous leaders doing, as they repeatedly aver, what Western leaders failed to do in 1938 and may be failing to do once again, or are reckless. No matter how they act, they will be judged harshly.An Israeli attack prior to November would expose Israel to charges that it was trying to “play” the American electoral cycle to its own advantage, even if the two were totally unrelated, and should be avoided. Immediately thereafter, however, Israel should demand clear assurances from the next president regarding his intentions, which would be more difficult in the event of a Romney victory, and which leaders are admittedly always loathe to give. After years of discussion, the two sides will finally have to put their cards on the table and make a decision.If Obama is elected, but maybe not if Romney is, there may still be time for one last diplomatic push, but only if backed up with a clear threat and deadline, and the US should put a far more generous proposal on the table, so that no one can argue that it has not fully tried. Simply strengthening sanctions will no longer cut it, it is too late for that.The next president will rapidly have to choose between an American naval blockade of Iran, as a prelude to direct attack, should this be necessary; defacto acceptance of Iran as a nuclear power, along with various attempts to promote deterrence and containment, possibly through security arrangements with Israel and Arab countries; an American military strike, or acceptance of an Israeli one.Israel, too, will have to decide between an attack, or relying on its own and American deterrence. If the former, a major peace initiative would help deflect some of the criticism.The choices are harsh, but they are the available choices and time is now measured in months, not years. Otherwise we may truly find ourselves in a situation of too soon... too soon...sorry, too late.