What assets and weapons systems would the U.S. military likely use in any strike against Iran's nuclear program, and what targets would it seek to use them against?
Historically, the military has used just two carrier groups for actions in the Persian Gulf. That was the deployment before Operation Desert Strike, a two-day bombing campaign in 1996, and Operation Desert Fox, a three-day bombing campaign two years later -- both against targets in Iraq.
The capabilities of carrier groups are boosted by Tomahawk cruise missiles, which can be carried by cruisers, destroyers and submarines. With a range of up to 1,500 kilometers and the ability to hit targets with precision, the missiles are likely to be part of any attack.
But despite undeniable improvements in recent years, carrier-based air power still has limitations. A carrier strike group has far less actual attack planes than an Air Force air wing, and the planes it does have are of shorter range.
Patriot air defense systems might be deployed to U.S. allies in the gulf in an effort to offset any Iranian retaliation aimed at them. And there may be deployment of some of the U.S. European-based missile defense assets to Israel, just as there was before Gulf II.
There would also likely be the deployment of mine sweepers to keep sea lanes in the Persian Gulf, particularly the Strait of Hormuz, open.
One would also likely see deployment of additional U.S. fighters and fighter-bombers onto bases in Iraq, and maybe some into Afghanistan.
But the best indicator of a forthcoming attack would be the forward deployment of large numbers of KC-10 and KC-135 refueling tankers. An attack using U.S.-based bombers would require lots of tanker support, staging from places like Diego Garcia in the Indian Ocean, Bulgaria and Romania.
The existence of bases in Iraq and Afghanistan capable of handling the full range of U.S. fighter-bombers greatly expands U.S. Air Force capabilities for such an attack. But the central role is likely to played by the 22 B-2B "Spirit" bombers, which are based at Whiteman Air Force Base in Missouri and can be hosted at U.S. bases on Diego Garcia and Guam in the Pacific and at RAF Fairford in Great Britain.
B1-B and B-52H bombers would likely make additional strikes. Like the B-2 they have the range to launch attacks on Iran from distant locations and great payload capabilities -- the B-52H carries up to 70,000 pounds of bombs and can launch cruise missiles, which neither of the other aircraft can accommodate.
Supporting aircraft would likely include E-3 AWACS command and control planes, and larger strikes might include the use of smaller aircraft for precision strikes such as the F-15E Strike Eagle and F/A-18 Hornet, both of which are equipped to carry special penetrative munitions. Such a strike could witness the combat debut of the F-22, currently based at Langley AFB in Virginia.
Pentagon officials have identified 1,500 "aim points" -- distinct targets -- in Iran's nuclear complex. Hitting them all, or even most of them, would require at least hundreds, if not thousands, of sorties.
Analysts like Michael Eisenstadt of the Washington Institute for Near East Policy have urged the destruction first and foremost of facilities used to produce the components for the centrifuges that Iran is using for uranium enrichment.
"It would be desirable to destroy workshops engaged in the production of centrifuge components as soon as possible," he wrote. It might make sense to wait to strike some other facilities, especially those still incomplete. "Striking facilities that are in the early phases of construction now would yield little benefit; it would make sense to wait until they are closer to completion, although protective measures at these sites might well improve with the passage of time."
Still, by definition, any attack on Iran's nuclear program could not be a so-called surgical strike. The Iranians remember very well from Israel's 1981 lightning strike against Iraq's Osirak nuclear reactor. They have dispersed their nuclear facilities and buried some of them deep underground. Satellite images suggest the Iranians have constructed underground chambers, protecting their equipment with as much as 45 feet of reinforced concrete and dirt.
Osirak, on the other hand, was just one, easily identified, above-ground site.
Moreover, Iran's nuclear facilities are located near densely populated towns, and those living or working nearby would be at serious risk. For example, bombing the uranium conversion facility at Esfahan is complicated by the uranium stockpile already there. Destruction of the facility will certainly result in the release of tons of uranium hexafluoride and other fluorine and uranium products into the atmosphere.
In addition to the environmental contamination due to the release of uranium, the presence of fluorine in the atmosphere will almost certainly result in significant production of hydrofluoric acid, an intensely corrosive substance that has the potential to cause extensive damage. Adding to the potential for civilian casualties is the proximity of the city of Esfahan, a metropolis of close to 4.5 million people.
According to Anthony Cordesman, an analyst with the Center for Strategic & International Studies in Washington, Iran has clustered land-based air defense systems -- U.S.-made Improved Hawks dating from the 1970s and Soviet-era SA-2s -- around some obvious targets, such as the uranium enrichment facility at Natanz, south of Tehran, and the heavy-water reactor at Arak, southwest of Tehran.
Another obvious target is the Russian-designed reactor being built at Bushehr, along the Persian Gulf coast. But it is a risky target because of the several hundred Russian workers there who might be killed.