On Sunday afternoon, in the midst of considerable disagreement with Washington over Iran policy and hours after the Geneva talks between Iran and the world powers ended without agreement, Prime Minister Binyamin Netanyahu took to the US airwaves to present Israel’s case to the American public.“I think the president and I share the goal of making sure that Iran doesn’t have nuclear weapons,” Netanyahu said with tremendous understatement on CBS’s Face the Nation, referring to US President Barack Obama. “I think where we might have a difference of opinion is on how to prevent it.”To which one could have been forgiven for shouting at the television, “Ya think?!” Saying that Jerusalem and Washington share the goal of keeping Iran from gaining nuclear weapons, and only differ on how to achieve it, is like saying two parents concur that they want their children to grow up to be good and decent human beings, and differ only on the educational philosophy needed at home to bring it about.What Netanyahu discussed is a pretty fundamental difference on a pretty significant issue. But, as a senior American official said in a briefing with Israeli reporters this week, that type of difference need not break up relationships. Husbands and wives love each other, the official stated, but that does not mean they don’t disagree and fight from time to time – nor that those natural fights and disagreements necessarily put the relationship in danger of collapse.Which is a valid point, one that everyone from US Ambassador Dan Shapiro to Intelligence Minister Yuval Steinitz were at pains to stress this week.“The truth is that the US and Israel have as close a relationship as any two countries on earth,” Shapiro said on one occasion. Steinitz said on another: “USIsrael relations are not good, they are very good.”BUT STILL, what emerged in the very loud, public and testy dust-up this week between the US and Israel over a proposed agreement with Iran on its nuclear program were basic conceptual differences about how best to approach the issue.Up until the June election of Iranian President Hassan Rouhani, when Mahmoud Ahmadinejad was ruling the Iranian roost and – because of his radical extremism – made it easier (though not easy) for Israel to rally opinion against Tehran, the differences over Iran had to do with timeline: when it would be necessary to act militarily to prevent Iran from getting nukes.This was the core of the disagreement last year over redlines for Iran, with Netanyahu urging for a redline to be set, and Obama unwilling to do so.The difference back then – pre-Rouhani days – could be summed up using a cake metaphor. Imagine you want to keep someone from baking a cake.What is the best way to do it? Do you prevent the prospective baker from gathering all the ingredients – the eggs, flour and water – and putting them on the table to mix together and place in the oven at his pleasure (the Israeli position)? Or do you say you have time, and can wait to physically stop the baker if he dares to stick head and hands into the oven to remove the cake once it is baked (the US position)? The entire debate over redlines was a discussion over whether military action was needed to keep the Iranians from gathering all the ingredients needed for a nuclear bomb, but not mixing them together – or whether it was wiser to wait until they mixed all the ingredients together, and were just about to pull a finished bomb out of their centrifuge-spinning military/industrial ovens. That huge Israeli-US tactical difference could be explained by differences in proximity, threat perception and capabilities. Since Israel is so much closer to Iran than the US and feels so much more immediately threatened, and also because its military capacities are less great than those of the US, it does not feel that military action could be delayed until the very last minute – like the US. Rather, Israel asserted that military action would have to be taken to keep the Iranians from getting all the ingredients together on the table.That was Netanyahu’s famous redline on a diagram of a cartoonish looking bomb at the UN in 2012; a redline defined as the Iranians acquiring 250 kilos of uranium enriched to 90 percent – a redline, by the way, that the Iranians have been careful not to cross.That was then. Now, with Rouhani’s election, the discussion has shifted and is less about a redline for military action, and more about the efficacy of diplomacy, and how best to get the Iranians to back off.Here, too, a cake metaphor can illustrate the differences.If you don’t want the persistent baker to bake his cake, and are physically twisting his arm to keep him from doing so, do you take the pressure off his arm when he says he is no longer interested in the same type of cake and agrees not to touch the ingredients on the table for a while? Or do you only start letting up on his arm when he pours a good amount of the eggs, flour and water down the drain so he can’t make the cake, even if he might still want to? And therein lies the major conceptual differences in the US and American approach. Those differences can be seen along two major planes. The first plane has to deal with the idea whether the P5+1 – made up of the US, Russia, China, France, Britain and Germany – should pursue an interim agreement or move only toward a final one with the Iranians, and the second has to do with sanctions.Regarding the type of agreement to pursue, according to the American approach – as articulated this week by a senior American official who briefed Israeli journalists – the proposal put on the table in Geneva was a first stage agreement.The idea, she said, was to get the Iranians to freeze their nuclear program for six months, and then use those six months to negotiate a comprehensive agreement on the nuclear program.The guiding philosophy here is it will take much longer than half a year to negotiate a comprehensive deal, but that it was necessary to ensure that during these negotiations, the Iranians don’t use the time to “run out the clock” – meaning that as the negotiations plod on, they don’t use the time to continue spinning their centrifuges.The approach advance by the US is to get the Iranians to freeze their program for six months, thereby putting some more time back on the clock for negotiations, and in return grant the Iranians some sanctions relief.Israel has a couple of problems with that approach.The first is that it believes that if everything is frozen for six months, then Iran – for the first time – would gain international legitimacy for being a nuclear threshold state, something it will then be more difficult to roll back.“Iran became a de facto nuclear threshold state 12-18 months ago,” Steinitz declared this week, saying this means that once it makes a political decision to go for a bomb, it would take it less than a year to do so.Up until now, Steinitz said, this threshold status for Iran has put it in clear violation of international law, of UN Security Council resolutions and of various stipulations of the International Atomic Energy Agency.“Now after this interim partial agreement, Iran is actually in a very sophisticated way achieving international legitimization for being and remaining, a least for the time being, a threshold nuclear country,” he said. “It is the most dangerous thing, and it will be more difficult later to roll back their capacity, because once you give it some kind of international legitimization, it is very difficult to say it is impossible, not legitimate.”Or, as Home Defense Minister Gilad Erdan put it even more bluntly later in the week, “We must not be mistaken: An interim agreement will be a permanent agreement.”Steinitz said that Israel adamantly opposes a partial agreement with Iran, because Jerusalem believes in the formula that “the greater the pressure, the greater the chances for diplomacy to succeed.”If you accept that principle, he continued, “it logically follows that the lower the pressure, the lower the chances. So the conclusion is clear: Don’t ease the pressure on the Iranians until you reach the final goal, before you reach a final comprehensive and satisfactory agreement. If you ease the pressure before that, you will lose the chances to succeed.”Or, as Defense Minister Moshe Ya’alon put it, if the Iranians are only freezing their nuclear program, and not taking any significant steps to dismantle their centrifuges and actually roll their program back, then the world should freeze its sanctions in place, but not begin to roll them back.A freeze for a freeze, he said, a rollback for a rollback; but definitely not a rollback of sanctions for only a freeze of the nuclear program.Which leads to the second major conceptual difference with the US, and that has to do with sanctions – both how the Iranians will respond to heavier ones, and how to keep the world on board. These differences are larger even than the spat Wednesday between Washington and Jerusalem, about whether sanctions relief offered to the Iranians was “moderate” as the US claimed, or reached up to $40 billion, as Steinitz maintained.ACCORDING TO the US way of thinking, if some sanctions relief is not provided in the midst of negotiations, certain countries that have been difficult to get onboard – but which are now onboard – will view this as unreasonable and begin to abandon the sanctions ship. The countries that come to mind in this context are China, Russia, Turkey, India, even South Korea.The senior US official said that if sanctions are not relieved, but indeed more sanctions are piled on – as the US Senate is considering – two things would happen: Iran would leave the negotiating table and move more aggressively forward in its nuclear program, and the international coalition in place would say the Americans were just pressing for military action, deem this position unreasonable and begin to abandon sanctions altogether.Israel believes the opposite.Tougher sanctions, or at the very least not removing sanctions, would not embolden Iran to move more aggressively forward in its nuclear program, but rather render it more pliable – since the pressure of the sanctions is what brought Tehran to the table in a serious mood to begin with.Moreover, the sanctions regime won’t collapse with more measures, but rather would begin to unravel if it is relieved because – as Netanyahu said this week – if you punch a hole in a tire, it is just a matter of time before all the air escapes and the tire goes flat.Granted, as Netanyahu said on Meet the Press, the American and Israeli strategic goals on Iran are identical. The devil here is not in the details; rather it is in the significantly different approaches to the tactics.