A reporter last month asked Lt. Gen. Dan Halutz, the Israel Defense Force's chief of staff, how far Israel is willing to go to stop Iran's nuclear (weapons) program; the general answered: "2,000 kilometers" - the flying distance from Israel to Iran's key nuclear sites.

Keeping the military option on the table for dealing with the Mullahs of Mayhem's atomic intransigence makes good policy sense. Diplomacy and "soft power" options such as economic sanctions are always more effective when backed up by the credible threat of force.

Unfortunately, flattening Iran's nuclear infrastructure isn't easy or risk-free - and could have serious consequences for American interests. The key challenge: the program is underground - literally and figuratively.

Iran burrowed many sites deep below the soil, making them much tougher targets. (It also put some near populated areas to make civilian casualties a certainty if attacked.) And these are the sites we know about: At least two dozen nuclear-related sites are scattered across the country (which is four times California's size) - but it may be more than 70.

By burying and dispersing its facilities, Iran is clearly trying to avoid the fate of Saddam Hussein's nuclear program back in 1981 - when Israeli F-16 fighters, crossing Jordan and Saudi Arabia, destroyed Iraq's 40-megawatt Osiraq reactor in a dawn raid, effectively setting Saddam's nuke dreams back a decade.

An Israeli strike at Iran today might feature fighters carrying satellite-guided JDAM bombs, cruise missiles on diesel subs - and Special Forces. But the task would be much tougher than the Osiraq strike, thanks to the number of targets and their dispersion, and the greater distances from any Israeli base.

What about U.S. airstrikes? These could take a range of forms, depending on policymakers' desires. Surgical strikes might limit their targets to Iran's air defenses (for access) and key nuclear sites (e.g., Bushehr, Nantanz, Arak). Or an escalated attack could nail all suspected nuke facilities - plus forces Tehran might use in a counterattack, such as its ballistic missiles and conventional forces.

Depending on the strike's objective, think Operation Iraqi Freedom: B-2 stealth bombers carrying bunker-busters, F-117 stealth fighters and other Navy/Air Force strike assets from carriers and theater bases - plus Navy destroyers and subs loosing cruise missiles on Iranian targets.

But could a raid destroy all sites? Thanks to the covert nature of the Iranian program, that's not clear. It's highly likely, though, that striking key facilities would set the program back, possibly causing Tehran to reconsider the folly of its proliferation perfidy.

But it's unlikely to be that simple. After an assault, Iran might lash out with a vengeance. We'd have to be fully prepared for some nasty blowback.

Tehran and its terrorist toadies can brew up some serious trouble for both America and Israel - or anyone else that supported an attack on the fundamentalist Islamic state.

The Iranian regime is already up to its neck in the insurgencies in Iraq and Afghanistan. It could certainly increase its financial/material support to the Sunni insurgents, Shia militants, al Qaeda, and the Taliban to destabilize the new Baghdad and Kabul governments - and kill Coalition forces.

And don't forget about Iran's other "secret" weapon - oil. As the world's No. 4 oil exporter, Tehran could rattle oil markets and major economies (e.g., Japan, South Korea, France, Italy) by slashing output. It could also mess with other nations' oil exports - attacking tankers in the Gulf using mines, subs, patrol boats or anti-ship missiles.

The mullahs could unleash their terrorist attack dogs Hezbollah, Hamas and Palestinian Islamic Jihad against Israel, killing untold numbers in suicide attacks - and scuttling any peace process prospects. Iran could also pound populous Tel Aviv with its Shahab missiles mated with chemical/biological warheads.

The U.S. homefront could get hit, too. Over the last few years, the FBI has evicted Iranian intel officers for surveilling New York City tourist/transport sites. Hezbollah has supporters - and likely has operatives - in America who might undertake acts of terrorism or sabotage U.S. ports or bases, too.

Iran now harbors at least 25 senior al Qaeda operatives, including senior military commander Saif al Adel and three of Osama bin Laden's sons. If we come to blows, would Tehran help al Qaeda hit the U.S. homeland? (The offices of Iran's U.N. mission might facilitate such an attack. . .)

This doesn't mean we shouldn't use military might to interrupt or end Iran's nuclear gambit; it may be the best/only option. There are no easy answers, only tough choices.

But the military option has to stay on the table. Otherwise, it's a snap that Iranian President Mahmoud Ahmadinejad will let Tehran's nuclear genie out of the bottle.

Peter Brookes is a Heritage Foundation senior fellow. His book, "A Devil's Triangle: Terrorism, WMD and Rogue States," is just out.