[cross-posted at Current Intelligence]

Earlier this week, President Obama announced the end of America’s combat mission in Iraq and pledged his commitment to begin drawing down American forces in Afghanistan beginning next summer. A key theme in his address to the nation was the need for the United States to redirect resources from nearly a decade of two wars and invest in the economy at home. Yet, although the President is trying to move away from an era of “perpetual war,” Washington is already abuzz about the next impending military action the region: an Israeli strike on Iran, which would likely disrupt US objectives and operations in Iraq and Afghanistan and create enormous political, strategic, military, and economic costs to the United States around the globe.

Jeffrey Goldberg triggered the most recent discussion with his article “Israel is Getting Ready to Bomb Iran: How, Why – and What it Means” in the current issue of The Atlantic. Based on dozens of interviews over the past few years, Goldberg’s assessment is that most Israeli leaders (and citizens) now view a nuclear Iran as an existential threat and, as a result, there is “better than a 50 percent chance Israel will launch a strike on Iran by next July.”

I spent a couple of weeks in Israel in June also talking to senior Israeli political and military officials and I came away with a similar impression. The Israelis will not tolerate an Iran with nuclear weapons and they will take military action to slow it if no one else does.

To be sure, there is a possibility that the Israeli government is sounding particularly hawkish as a signaling ploy to generate a stronger international response to Iran’s nuclear weapons program. But I concur with Goldberg’s assessment that the current Israeli leadership under Prime Minister Benjamin Netanyahu believes the existence of the state of Israel and the entire Zionist movement is threatened by a nuclear Iran. They see the threat as both direct – a nuclear Iran will act more aggressively by unleashing Hezbollah and Hamas to launch direct attacks on Israeli cities – and indirect – as the next generation of educated Israelis will leave the country for the relative safety and comfort of the United States or Europe. As a result, both the security and demography of Israel will be irreparably changed.

Regardless of whether or not this is the true nature of the threat, and whether or not a nuclear Iran could be contained, the dominant view in the upper echelons of the Israeli government is that Iran with a nuclear weapon cannot (and will not) be tolerated.

I’ve spent the past twenty years studying decisionmaking and war. Decisions for war are often a confluence of heightened assessments of threat coupled with various psychological or ideological biases that discount the costs of war. In this sense, decisions for war are more likely when leaders perceive an enemy as a paper tiger – ferocious and dangerous if left unchecked, but easily dismantled by swift and concentrated military action. In these circumstances, war becomes more likely when it is seen as both a necessary and relatively low cost instrument.

What is striking about the debate in Israel today is that no one seems to be discounting the costs to Israel if it does strike Iran. The Israelis that I met with all agreed that Israel would be isolated in the world if it launched a preventive attack. It would trigger large-scale retaliations by enraged Iranians and radicalized Muslim populations against Jews and Jewish interests around the world. The Israelis also expect that an attack would imperil the Palestinian Authority’s statebuilding efforts on the West Bank and trigger counter attacks against Israel from Hezbollah in southern Lebanon and from Hamas in Gaza. Israeli intelligence officers told my group that it believes Hezbollah and Hamas have acquired somewhere between 40,000 and 45,000 rockets from Iran in the past several years. These weapons are more sophisticated and longer range than Qasam rockets used by Hamas in Gaza and can now strike almost every city and town in Israel. This would compel a full-scale land campaign by the Israeli Defense Forces in both Gaza and Lebanon.

And, finally, the Israelis are conscious that a strike would trigger a reaction against American military personnel and interests throughout the Muslim world. This would profoundly affect all American efforts in Iraq, Afghanistan, and Pakistan. More broadly, it could seriously destabilize the entire Persian Gulf and broader Middle East, and be disastrous to the global economy.

Even with this analysis in hand, many in the Israeli leadership appear to believe that striking Iran would be the best option if nothing else is done to prevent Iran from developing a nuclear weapon.

The challenge for the Obama administration in the coming months is to simultaneously deter Iran from moving forward on its nuclear weapons program while persuading the Israelis not to take matters into their own hands. This will not be easy. The Iranian regime has shown little sign of altering its course. Constraining the Israelis – difficult under any circumstances – will be considerably more difficult after the mid-term elections in November if the hawkish, pro-Israeli Republicans do as well as expected.

Obama entered office as the most boxed-in President since Harry Truman – facing two wars and a global financial crisis. But it is this situation that may be the biggest challenge for his Presidency, and the most dangerous. If Obama fails and the Israelis strike, the regional and global reaction to both Israel and the United States will be severe. We almost certainly will be looking at a fundamentally altered environment, in security and economic terms, for the next generation.