At some point, military leaders in the United States and in Israel will have to decide: Which is more dangerous -- an Iran capable of launching a nuclear weapon? Or an Iran that just got hit with tons of artillery and is out for revenge?
Both scenarios are frightening, particularly to the Israelis. U.S. officials have described the prospects of a nuclear-armed Iran and a military confrontation as equally terrible, particularly at a time when the Obama administration is trying to end nearly a decade of war in Iraq and Afghanistan.
But the thought of military action is not far-fetched. The United States acknowledges it possesses an attack plan for Iran, and the Israelis reportedly have drawn up specific scenarios for a strike.
What such an attack would look like, who would lead it and what the consequences would be are open questions -- and ones that several top analysts and former officials have tried to answer. Based on those reports and conversations with analysts, the following are some of the most common predictions on what Iranian airspace would look like if the U.S. or Israel were to decide, in answer to the first question, that a nuclear-armed Iran is worse than an angry one.
The first scenario resembles a shot across the bow, only this one actually hits something. Kori Schake, an associate professor at the U.S. Military Academy at West Point and a former member of the National Security Council staff during the Bush administration, called this option a "demonstration strike."
Under the scenario, the Israelis would strike one or two sites in Iran to show they're serious, but they would try to avoid casualties. Iran's energy ministry, for instance, could be a symbolic target if it were attacked after hours.
The downside, Schake said, is that Iran would be left with "wide latitude" for retaliation, considering its infrastructure would be intact. Schake said she would not advise this option.
Even under this limited-strike scenario, Israel would be confronted with important logistical hurdles -- the kind of which would have to be resolved before any confrontation.
Unlike Israel's 2008-09 campaign in the Gaza Strip, its Air Force would need to fly through the airspace of other sovereign nations to hit Iran, most of which are not considered Israel sympathizers. The possibilities include Saudi Arabia, Turkey, Syria, Jordan, Kuwait and Iraq -- depending on what route the Israelis take.
There are also refueling concerns. While Israel's F-15s and F-16s could handle the job, analysts say, the targets would be a stretch for the aircraft's range -- limiting the amount of time the jets could spend over their targets and probably requiring midair refueling.
Then there's the question of what Iran would do in response.
The option at the top of practically every list of scenarios is one in which a handful a high-level targets are selected for destruction. This includes, but is not limited to: the uranium-enrichment facility at Natanz, the enrichment site at Qom, the uranium conversion facility at Isfahan, the heavy water reactor at Arak and the soon-to-be-live nuclear reactor at Bushehr. The last would be less likely, because after Iran begins loading up the fuel rods this weekend, the radiation danger from an attack might be too great.
The Council on Foreign Relations released a memo last fall examining exactly this kind of strike, leaving out Bushehr and putting Israel, not the United States, in charge of the attack. The study said Israel would have the munitions, particularly the bunker-busting BLU-109 and BLU-113, to "severely" damage the targets and penetrate deep enough to get at the largely underground Natanz facility.
"This would be possible even if Iran managed to down a third of the Israeli strike package," the memo said.
The upside of such an attack is that -- unlike Option 1 -- it both sends a signal and damages Iran's nuclear infrastructure.
"If I were an Israeli strike planner, I'd be looking for things that, if destroyed, would really set their program back," said Steven Simon, a former National Security Council official who wrote the CFR report.
Schake said that by targeting just the nuclear-related sites, the argument could be made that it was an attack on the nuclear program alone, and not the Islamic Republic itself.
"An all-out Middle East war," said Sam Gardiner, a retired Air Force colonel and former faculty member at the National War College who has helped conduct a number of Iran war games.
Once Israel starts going after high-value targets, Gardiner said, the United States will inevitably be drawn into the conflict. He, too, named Natanz, Arak and Isfahan as the top targets, but he said Iran could wreak all kinds of havoc in response. The country could pull strings in Iraq, Yemen, Gaza and Afghanistan, among other places, to target U.S. troops and allies. He said the Iranians have substantial chemical weapons, and probably biological weapons, with which to retaliate, even if they haven't produced a nuclear bomb. And Israel is close enough to be an ideal target.
"One has to be careful not to make the Iranians too mad," Gardiner said.
Another downside is that an attack could help Iran's regime consolidate power -- Defense Secretary Robert Gates warned last year that the regime could wind up stronger for it.
Officials and analysts, including Gates, also warn that no military campaign will fully cripple Iran's nuclear program. The strikes are viewed more as a way to delay, not halt, Iran's nuclear progress.
The New York Times reported Thursday that the Obama administration has assured Israel that Iran is at least a year away from obtaining a nuclear weapon, presumably reducing the chances of an imminent strike.
Shock and Awe
Though Israel's strikes against an Iraqi reactor in 1981 and a Syrian reactor in 2007 set the precedent for another attack in Iran, an air campaign on Iran's nuclear program would look completely different today. The most extreme scenario for an Iranian strike underscores this.
The last option is an all-out air attack on Iran's infrastructure, hitting all or most of the known nuclear targets in the country, in addition to security and military targets like Iran's Revolutionary Guard Corps and even economic targets like refineries.
It is likely, analysts say, that the United States would have to spearhead such an attack and tap its resources throughout the Middle East to do so.
A report on GlobalSecurity.org said a U.S. air strike would "vastly exceed" the scope of the 1981 attack on Iraq and look more like the 2003 opening assault on Iraq. The GlobalSecurity report said B-2 stealth bombers, F-15s, F-16s, cruise missile-mounted destroyers and other assets would be at the United States' disposal.
Simon, who served with the NSC during the Clinton administration, co-authored a column with President Obama's former Iran adviser, Ray Takeyh, this month noting that the U.S. would need to have some degree of support from the Gulf nations to leverage those assets.
"The U.S. Fifth Fleet is headquartered in Bahrain; the Combined Air Operations Center is in Qatar; prepositioned materiel for ground and other forces is in Kuwait and Oman; and the United Arab Emirates offers extensive port facilities and staging for tactical aircraft," they wrote. "A campaign against Iran would require not just the acquiescence of these governments but their willingness to absorb retaliation by a bruised and outraged neighbor for years to come."