There is no reason for so much as a "crack" in relations between our government and Obama's, Shimon Peres said this week. He's wrong. On Iran, the Israeli and American red lines are drawn in very different places. Welcoming the 2002 Arab League peace initiative, all but endorsing a two-state solution, insisting that the new Israeli government was determined to make peace, President Shimon Peres turned in a vintage performance at the AIPAC annual Policy Conference this week. He sent chills with his warnings about the aggressive Iranians' nuclear threat and hegemonic ambition, warmed hearts by talking of his two great-grandchildren, Ella and Ari, as their adorable features flashed on the giant video screens, and served as the model visitor by paying a warm tribute to the host nation and its new leader. Barack Obama's election, he declared, had unleashed a "tsunami" of hope - and we in Israel, he promised, were going to help Obama realize it by opening our arms to reconciliation with the Arab world. Departing the stage, the applause ringing in his ears, Peres was ushered toward the shortest of briefings for the Israeli media, and delivered a couple of quotes for our TV news cameras. The vexed issue of the two-stated solution, notably not endorsed to date by Prime Minister Binyamin Netanyahu? "We'll deal with it," Peres assured Channel 10. Potential problems between the Netanyahu and Obama governments? "No reason for so much as a crack," he declared to Channel 2. A partnership without cracks? Not quite, Mr. President. Commentators are hyping several avenues of potential collision: Those discrepancies on the "two state" vision, for a start - which are likely to be finessed, if not fully resolved, when Netanyahu meets Obama on May 18. The knottier question of how Netanyahu can keep both the US and his domestic hawks happy on the issue of settlement growth and illegal outposts. And finally, the differences of opinion about where progress must and can first be made - on Israeli-Palestinian peacemaking (the apparent American game plan) or on thwarting Iran (the Israeli conviction)? While some or all of these issues may indeed prove truly divisive, however, this year, in the briefing rooms of the AIPAC conference, as in the corridors of power back home in Israel, the contours were discernible not merely of a crack, Mr. Peres, but of a veritable abyss between Israel and America - a rupture that goes far beyond rhetorical gaps and conflicting emphases. Israel is sounding increasingly jittery about that Iranian march to the bomb. And its criticism of the international community's failure to intervene effectively - which was primarily focused in past years on those hypocritical Europeans who talk tough on Iran but also trade healthily with it - is now focusing on the United States, as well. Where Iran is concerned, Israel's red lines are drawn in a very different - earlier - place than those of the United States. We worry - existentially - that the Iranians may use the bomb if they get it, or supply it to a third party. But short of its use, we worry about the shift in the Middle East balance of power that would be produced by a nuclear Iran; the regional nuclear arms race it would spark; the knock-out blow to Israeli-Arab normalization; the emboldening of Hamas and Hizbullah; and the greater indifference to international pressures that Iran would feel when considering which weaponry to provide for these vicious proxies to the top and bottom of Israel. And so, in 10 days' time, it can be safely assumed that Netanyahu will tell Obama flatly that Israel will not accept a nuclear Iran, and that the point of no return is looming - a message laden with implications regarding possible Israeli action in its own defense. Yes, Obama has repeatedly asserted that he will do everything in his power to prevent Iran attaining the bomb. But on the ground, or rather beneath it, at Natanz and Bushehr and a dozen other known sites and who knows how many more covert facilities, Iran marches forward. WHILE NETANYAHU has accepted that Obama's opening gambit, engagement, can be useful, the intended US timeline, the goals and the benchmarks currently lack cogent definition. Israel's leadership has come to fear that our country's existence is at stake, and America offers no solace. From Israel's point of view, it is the "breakout" capacity that must be prevented - the point at which Iran's bomb-makers have obtained enough sufficiently enriched uranium to be able to break out to the bomb as and when they choose. This means that the US engagement must have worked, or been deemed not to, by year's end at the very latest (but probably before, if those thousands of Natanz centrifuges keep spinning smoothly) - in order to leave time for further pressures and actions. The window for diplomacy could be widened if the Iranians agreed to verifiably halt enrichment while diplomacy proceeded, but nobody is betting on that. This breakout point is critical because, whatever the miscalibrated and amateurishly presented 2007 American National Intelligence Estimate might have asserted, Israel is convinced that Iran has everything else ready to go - that is, neither delivery systems nor weaponization constitute obstacles to the Iranian bomb any longer. That exceedingly grim Israeli estimate, furthermore, is echoed in a report produced on Wednesday by the US Senate Foreign Relations Committee, which said that intelligence analysts and nuclear experts working for unnamed foreign governments now believed "Iran had produced a suitable design, manufactured some components and conducted enough successful explosives tests to put the project on the shelf until it manufactured the fissile material required for several weapons." In his recent book The Inheritance, The New York Times' chief Washington correspondent David E. Sanger recalls an extraordinary briefing held in Vienna in February 2008 at which the IAEA's chief inspector Olli Heinonen presented a clandestinely obtained Iranian document showing the arc of a missile's flight. "It indicated when the altitude meters would be switched on, when the detonators in the warhead would be fired, and it showed the warhead exploding at about 600 meters above the ground," Sanger writes. "Heinonen's message was clear... As any nuclear weapons designer would attest, that is roughly the height at which an atomic bomb, detonated over a city, can do the most damage." Heinonen was not definitively proving that the Iranians were now making a bomb. But his document did demonstrate that Iranian engineers were tackling "the most difficult problems any bomb designer faces sooner or later: how to make a warhead small enough to fit atop a missile, and how to time its detonation." ISRAEL IS entirely convinced that the Iranians will not prove amenable to diplomacy, and broadly certain that Iran will not be shifted from its nuclear course by anybody or anything short of radical action. There are those who still nurture faint hope that sanctions will work - even though it is clear that Iran is already hurting and yet has speeded up its program. If Obama can get Russia and China on board, and genuinely coopt the hypocritical Europeans, some in Israel still believe, the economic pressures may prove sufficient. But these are big ifs, and for an Israeli prime minister who has spent many years trying in vain to persuade foreign counterparts of the gravity of the threat, the combination of international indifference thus far, and his sense of the mounting danger, are producing a sense of diminishing room for maneuver. In December 2006, holdover Defense Secretary Robert Gates told his Senate confirmation hearings that US military intervention to stop an Iranian bomb was an option to be considered only "as a last resort and if we felt our vital interests were threatened." (My emphasis.) That American position has not changed. Only last month, Gates reiterated that "a military attack will only buy us time and send the program deeper and more covert." Hearing that assessment today, some in our leadership seem increasingly uncertain that Washington, in this context, considers Israel a vital interest. For now, America is talking diplomatic engagement with no firm time limit, leverage via vital Iranian energy imports, and that pointlessness, or worse, of military action - which would only stir up a hornet's nest of Iranian revenge, inflame the international community, and dent but not destroy the nuclear program. While Israel insists its unspecified military option could guarantee heavy damage but not necessarily the destruction of the Iranian program, Washington notes that more than a dozen targets would have to be smashed for any likelihood of truly severe damage. This would require "in the neighborhood of a thousand strike sorties," according to an expert quoted by Sanger - and even then there would be no guarantee that replicated covert facilities were not left standing. In a bitter Jerusalem, the point is acerbically made that Gates's publicized reluctance for military action has taken all the pressure off Teheran. And if Teheran is not afraid of military action, runs the Israeli thinking, it will be all the more robust in resisting sanctions. VARIOUS UNCONFIRMED reports in overseas newspapers in recent months have indicated that Israel is planning seriously for the possibility that it may have to use its military option - planning all the more seriously as time has ebbed away and American will apparently ebbed with it. The Israel Air Force is said to have flown demonstrative rehearsal missions in the Mediterranean - substantial fleets of F-15s and F-16s replicating the long journey to Iran and back. It has been widely reported, furthermore, that Israel, last spring, losing hope of American action, sought, at least, American assistance: Mere months after his intelligence apparatus had removed his legitimacy for military action with the NIE, president George W. Bush is said to have turned down Israeli requests for both the weaponry - bunker-buster bombs - and the overflight cooperation for an Israeli assault on the Natanz enrichment facility. Gates reportedly argued decisively to Bush that a strike was unlikely to prove effective, would lead the Iranians to expel IAEA inspectors, remove any possibility of effective monitoring of subsequent activities and quite possibly ignite a regional war in which American troops in overflown Iraq would be especially prime and vulnerable targets. The rebuff has presumably necessitated Israeli reassessments and fresh approaches - to Washington's abiding dismay, according to Sanger. The US has been shuddering at the prospect of Israel's bombers overflying Iraq anyway, without approval. "Would the American military be ordered to shoot them down? Not likely," Sanger believes. "So, by the time the first bomb dropped, Washington would be accused of being complicit in the Israeli attack, whether the United States was part of it or not." It's "a nightmare," according to a US national security official. Israel is well aware of the range of immensely dangerous possible consequences of an attack. There could be Iranian missile strikes at Israel, for which the Arrow may or may not prove an adequate defense. Global terror would represent a profound challenge. Iranian threats to starve the world of oil exports, closing the Straits of Hormuz, are taken less seriously - since Iran itself depends on those exports. As for the key question of what an effective strike would achieve in the long-term - whether Iran would retain the will and the capacity to rebuild - that remains open. But in 1981, it is sometimes noted, Israel assumed its strike on Osirak would set back Saddam Hussein by a few years, and it turned out to have set him back for good. SANGER'S COMPELLING book, detailing the global challenges the Bush administration bequeathed to Obama, includes a remarkable passage on Mossad chief Meir Dagan's quiet visit to Washington two years ago, when Israel presented the US intelligence community with incontrovertible evidence that North Korean engineers had almost finished the construction of a nuclear reactor in Syria. That the US was blithely unaware of this - and had gone to war against a country that turned out not to have nukes, while entirely missing the construction of the nuclear facility next door - was an almighty intelligence failure. While Israel would have been proud of its clear-eyed scoop, it would have been deeply disquieted by America's blindness. Disquiet turned to dumbfoundedness when the US elected not to act. "The Pentagon developed a plan for a lightning strike," Sanger writes. And he says two senior US officials told him Bush seriously considered it. But ultimately, the US both chose diplomacy itself and urged diplomacy on Israel - "despite the fact that the Syrian reactor project was far more sophisticated than anything Saddam had under way in 2003." It was, as Sanger quotes a senior Israeli official as saying, "laughable logic." And so Israel, defying the US, took its defense into its own hands, smashed the al-Kibar reactor to smithereens, and - as with Osirak in 1981 - braced for repercussions that didn't come. PRESUMABLY, THERE have been similar quiet visits by the likes of Dagan to Washington where Iran, not Syria, was on the agenda - where Israel was bringing fresh intelligence that underlined the progress and the shortage of time. But as Sanger quotes a senior American official telling him in the wake of Israel's strike on Syria, the US "had post-Iraq syndrome, and the Israelis had preemption syndrome." Two traumatized leaderships, taking flawed decisions in the uncertain aftermath of past failures? The depiction is not entirely accurate. The US, which, under Bush, cried wolf with Saddam and then over-compensated with its devastatingly complacent assessment on Iran, is indeed, under Obama, still limited by "post-Iraq syndrome." But Israel does not have a preemption "syndrome." Rather, for better or worse, as it demonstrated first at Osirak, and more recently at Bashar Assad's secret al-Kibar facility, it has a preemption doctrine.