At the center of the public debate in Israel, and the controversy between Israeli and U.S. leaders, regarding a strike on Iran's nuclear facilities is the question: Can Israel trust U.S. President Barack Obama's promises to give the order for a military action before Iran acquires a military nuclear capability?President Shimon Peres represents the opinion that the United States does indeed "have Israel’s back" on the Iran issue, saying recently that he “trusted U.S. President Barack Obama to prevent the Islamic Republic from obtaining nuclear weapons.”However, the historical record of how U.S. presidents have dealt with the challenges set before them by the regime in Tehran contradicts this assumption. Public declarations by leading U.S. military commanders, most recently Chairman of the Joint Chiefs of Staff General Martin Dempsey, that he didn't want to be “complicit if they [Israel] choose to” attack Iran (but also Gen. Anthony Zinni, former Centcom Commander, Gen. Ron Burgess, director of the Defense Intelligence Agency, and Gen. Michael Hayden, former CIA and National Security Agency chief, who all warned against a military attack on Iran), has probably convinced the ayatollahs and the Iranian military commanders that there is little to worry about from the Americans.In addition, coverage in the U.S. media – most notably, this weekend’s Wall Street Journal editorial – has questioned the extent of the commitment to Israel over Iran that the current U.S. administration is broadcasting. The editorial concluded that Israel is justified in its concerns over the Obama Administration’s lack of straight-talking: what does it mean for Israel to hear that Obama is committed to countering Iran “even as his Administration tries to sell to the public a make-believe world in which Iran's nuclear intentions are potentially peaceful, sanctions are working and diplomacy hasn't failed after three and half years.”Let us examine the historical record in more depth. Former U.S. President Jimmy Carter not only didn’t lend a hand to Iran’s shah in confronting the Khomeinist Revolution, but he also didn’t manage to resolve the 1979-81 hostage crisis when American diplomats were held hostage for 444 days by the Tehran regime. And Carter lost his second bid for presidency.President Ronald Reagan, an acclaimed fighter against international terrorism, bombed Libya and Gadhafi’s Tripoli home after two American soldiers were killed in a bar in Berlin. Nonetheless, he did not dare challenge Tehran. He even ordered the withdrawal of the U.S. peacekeeping forces from Lebanon in 1984, after Hezbollah - with Iranian guidance and Syrian backing – blew up the U.S. Embassy in Beirut twice; caused deaths of 270 Marines in one suicide terrorist attack; kidnapped or murdered dozens of American citizens in Lebanon and hijacked U.S. airplanes in the area.President Bill Clinton knew exactly what role the Iranian intelligence played in the 1996 terrorist attack on the Khobar Towers in Dhahran, Saudi Arabia. Nevertheless, he preferred a covert negotiation with the "reformist" president Khatami (who remembers him today?) and kept the information secret so that he wouldn’t have to undertake punitive steps against Iran.President George Bush (Jr.), who hoped that the occupation of Iraq would help tighten the military noose around the neck of the rogue Iranian regime, did not retaliate against Tehran for its support for Muqtada al-Sadr’s Mahdi Army and other offshoot factions fighting American forces on the ground. Bush also preferred to give Israel the green light to bomb the Syrian plutonium reactor in 2007, rather than handle the new regional threat himself.The realization of the North Korean military nuclear project is a living example of Clinton’s and Bush’s unfulfilled promises to detach a rogue regime from its aggressive nuclear capabilities.President Obama's strategy has been to insist on the legitimacy of the UN Security Council and the international community before deciding on a military intervention abroad, as the Libyan and Syrian crises prove. How much time will he wait for Russian and Chinese support, let alone European support, for such an action?The American reticence to attack Iran’s nuclear project does not mean that Israel must renounce its aim of convincing U.S., European, and Arab leaders of the need for a military operation against Iran’s nuclear facilities. Many seem to prefer that Israel do the "dirty work" so that they can vilify it afterward.Israeli leaders should decide on an independent attack only at the last possible moment of the so-called "zone of immunity." They should resist the temptation to do it hastily, particularly before the outcome of the Syrian crisis is known, a crisis that has the potential not only to change the regional balance of power against Iran, but to bring about political and social upheavals inside Iran itself.