The United States must assure Israel that if it delays any military moves against Iran's nuclear program, Washington will use its own might to stop Tehran from weaponizing its nuclear program, former IDF intelligence chief Amos Yadlin wrote Thursday.US President Barack Obama must "shift the Israeli defense establishment's thinking from a focus on the 'zone of immunity' to a 'zone of trust'" Yadlin wrote in a New York Times op-ed. Last month, Defense Minister Ehud Barak alluded to Israel's "red line," when it might feel the need to attack Iran, describing that point as when Iran reaches a "zone of immunity" from an effective Israeli attack. "What is needed is an ironclad American assurance that if Israel refrains from acting in its own window of opportunity" to stop Iran's nuclear program, it will act itself to stop it. If Obama does not give Israeli leaders those assurances, Yadlin warned in the New York Times, Israeli leaders "may well choose to act while they still can."The op-ed by the former IDF intelligence chief and Air Force pilot, who participated in the Israeli strike on Iraq's nuclear program in 1981, comes days ahead of a visit by Prime Minister Binyamin Netanyahu to Washington. Scheduled talks between Netanyahu and US President Barack Obama were expected to focus on Iran, and especially on closing gaps between the two countries' definition of what constitutes a "red line" for Iran's nuclear program.Yadlin also indicated that Israel's capability to effectively strike Iran should not be underestimated. Asserting that the United States was taken by surprise by Jerusalem's ability to destroy Iraq's Osirak reactor in 1981, he said it would be a mistake to once again underestimate the IDF's ingenuity.Nonetheless, he admitted that the United States has military resources and technologies that allow it more freedom of action and the ability to carry out a deeper and more extensive campaign against Iran than Israel. Those capabilities, Yadlin explained, give Washington the luxury of more time to give sanctions and non-military measures a longer chance to become effective in stopping Iran's nuclear program.