The biggest mystery right now is whether Israel will attack or not. The American media are constantly addressing the issue – analyzing the hints, the subtext and the alleged differences between Defense Minister Ehud Barak and Prime Minister Binyamin Netanyahu; spending a lot of time – too much time – allowing every expert to contemplate if the IDF can or cannot do it; asking if Israel will or won’t tell the US ahead of time, speculating if anyone can stop the Israelis.Well, the truth is that US President Barack Obama has a quick and safe way to prevent Israel from attacking Iran.The writer is diplomatic correspondent for Channel 2 NewsHe should just say: “Trust me!” – but in a persuasive way.Obama promised the American people that the United States will not allow Iran to go nuclear. This was not said to please Israelis but to convey a strategic interest of the US. It is a promise that in every way is a test of the president’s leadership.If he does not keep his word, he will lose everything: his integrity, his support, the Middle East, his Arab allies. That’s why he must create a reliable threat that he is willing to act at some point, to give the order to the US military to attack Iranian nuclear facilities.To “speak softy and carry a big stick,” as Theodore Roosevelt once said.To stop an Israeli military attack, all Obama should do is to say that now. To offer Netanyahu a presidential guarantee, or even a secret letter, specifying that if certain red lines are crossed, this will lead to an American attack.It won’t be easy. Israel’s leaders abide by the “Holocaust-DNA,” meaning that when they swear “Never again!” they also mean that even their closest ally – the United States – cannot be fully trusted.As David Makovsky wrote in Foreign Policy: “Many Israeli military leaders are children of Holocaust survivors who joined the Israeli army to ensure Israeli self-reliance in fighting against enemies who regularly pledge to eradicate it. A poignant reminder is the iconic photo of Israeli jets flying over Auschwitz in 2003, which hangs on the walls of many of their offices.“Nonetheless, it is a fundamental misreading of Israel to view this as an ideological issue. Israeli considerations of a strike are rooted not in their ethos of self-reliance, but in the fear that the United States will ultimately fail to strike, even if sanctions fail.”This means that IDF officers and Israeli political leaders remember that the US knew about Auschwitz but did not act in time. The toll was millions of Jewish lives.Having said that, an honest proposal by the US would lead, at least, to a debate in the cabinet. Not all Israelis cabinet ministers are enthusiastic about military action. This can be the means to force an internal Israeli debate.It can be the alternative to the “no-other-option” campaign.Politically, it would be the ultimate proof of Obama’s support for Israel, an answer to all the Republicans who accuse him of not being pro-Israel enough.Strategically, it would be the almost the only way for the US to leave Iraq and Afghanistan not as losers but strong and proud, not as a nation running away from the Middle East but as one dealing with the dangerous forces in it differently and effectively.The only problem with such an “insurance policy” against an Israeli attack is that the red lines could be crossed and the words could turn into a new American war in the Middle East.That is not an easy decision – but it is, perhaps, the only one that leaves control in American hands.