In late December, Tehran crowed that its 1,000-megawatt Bushehr nuclear plant, supposedly meant to produce peaceful nuclear energy, would be "online" as early as this spring, cementing in place another important building block of its questionable nuclear program.

While the builders of the Bushehr plant, the Russians, insist the plant will not be completed until the end of the year, Moscow did make the first of several deliveries of fuel rods to Iran in late December.

This unwelcome news comes as Iran is continuing to spin as many as 3,000 centrifuges to enrich uranium, ostensibly to produce low-enriched uranium reactor fuel, but which could also be used to make highly enriched uranium (HEU) for nuclear weapons.

Indeed, while Iran is planning for some 50,000 centrifuges, some experts believe that just these 3,000, if running efficiently and 24/7, could produce enough HEU for one bomb in a year.

Enter Israel

This sort of news cannot help but rattle even the steadiest of policymakers' nerves, no matter what the narrowly focused National Intelligence Estimate (NIE) said about the current dormant state of Iran's nuclear weapons program -- especially in a country like Israel. While Israeli intelligence reportedly has no new -- or different -- information than that contained in the American intelligence assessment, it draws a very different conclusion than the U.S.: Israel believes the weapons program continues. You have to wonder, then, if Israel -- the country most threatened by an Iranian nuclear (weapons) breakout -- might take matters into its own hands. It has done so at least once, and maybe twice, before. And considering that an American strike on Iran's nuclear facilities is likely off the table for the moment, due to the NIE, the time may be here -- again -- for the Israelis to take action.

Indeed, Lt. Gen. Gabi Ashkenazi, the Israeli Defense Forces' (IDF) chief of staff, said at a December conference in Tel Aviv: "It's up to the international community to act in a determined way to stop Iran's nuclearization. ... But at the same time we have the responsibility to prepare for any scenario in the event that international efforts do not succeed."

That sort of no-nonsense, self-help attitude seems to be backed up by the IDF's record against regional nuclear programs that the Israelis have perceived as serious threats to their national security. In a 1981 dawn raid lasting less than 90 seconds, IDF fighters attacked the nearly completed 40-megawatt Iraqi Osirak nuclear reactor complex south of Baghdad, setting back Saddam Hussein's ability to produce fissile material for nuclear weapons. And again in September, the IDF appears to have struck a nascent Syrian nuclear program, which was possibly benefiting from outside help, in a preventive airstrike that may have also been meant as a warning to Iran of unpleasantries to come.

Eyes on Iran

So, could Iran be next? It just might be, especially considering the new timelines revealed by the Iranians involving the construction, fueling and initial operating capability of Bushehr -- not to mention an influx of new weaponry. It is possible that within about a year of Bushehr becoming operational, some of its spent nuclear fuel could be stripped of enough plutonium to produce a handful of nuclear weapons if the rods are not returned, as agreed, to their owner/supplier, Russia.

Because the production of sufficient fissile material is the most challenging task in constructing a nuclear weapon, the diversion of material at Bushehr is potentially as big a problem as the 3,000 centrifuges Iran has currently whirring at supersonic speeds, enriching uranium.

Attacking Bushehr -- like Osirak -- before it comes online would not only stop it from being used to produce fissile material for weapons, but would also prevent radiation from being spewed into the atmosphere after a strike.

Also possibly spurring the Israeli government into action sooner rather than later is other recent unpleasant news: Iran's defense minister announced in December that Tehran is buying the highly capable Russian S-300 air-defense system. The sale of the strategic S-300 (SA-10/Grumble) will complement the $700 million in Tor-M1 (SA-15/Gauntlet) short-range surface-to-air missile systems Moscow supplied last year, further enhancing Iran's air defense network. (The Russian defense ministry denied the sale of military equipment to Iran in a likely effort to avoid unnecessarily further cooling Moscow's already frosty relations with Washington -- or roiling the water with other regional countries concerned with such a transfer.)

Iran likely purchased the Tor-M1 to stave off a repeat of Israel's success against Osirak -- or the possibility that the U.S., well-suited for an air- or sea-based strike, would take action against Iran's nuclear program. The long-range S-300s -- likely a response to the IDF's September strike on Syrian facilities -- will enhance Iran's ability to protect its nuclear sites scattered around the country, some of which are already ringed with air defenses. (While understandable, considering the saber-rattling coming from a number of corners, it is curious the extent to which Iran is willing to go to protect its so-called "peaceful" nuclear program with military might.)

Iran is also suspected of possibly having a new ballistic missile, the Ashura, with a 1,200-mile range, capable of reaching Israel -- and beyond. It is not clear whether the missile is being produced, or has, in fact, been tested by Iran, as Tehran claimed in late November.

Tyrannies of Targeting

But despite these possible proximate reasons for the Israeli government giving the "go-ahead" for an attack on Bushehr before it is up and running, successfully dealing militarily with Iran's nuclear program is no small task. First, while Bushehr is certainly a key element in Iran's vast nuclear program, due to its ability to produce large amounts of bomb-worthy fissile material (i.e., plutonium) for weapons use, it is not the only element that needs to be addressed. To cripple -- or at least set back -- Iran's nuclear program, the IDF would have to hit other major sites: the Natanz uranium enrichment plant, the Arak heavy water facility and the Isfahan uranium conversion complex, plus, possibly, tens of other nuclear-related sites around the country. (The Iranians are also reportedly building a 40-megawatt research reactor at Arak, which, like Osirak, is too small for power production, but just right for the production of plutonium from its spent fuel, according to experts.)

There's also the tyranny of distance. Iran is a lot farther from Israel than Iraq -- and the targets are not conveniently clustered like at Osirak. They're spread across Iran -- a country nearly four times the size of California (or neighboring Iraq). Since key targets are out of range of Israel's ballistic missiles, the routing of strike packages would also present significant challenges. This raid would be more difficult that the Osirak raid in which IDF fighters slipped with impunity along the Jordanian and Saudi borders. Besides the most likely flight skirting Jordan and Saudi Arabia en route to Iran, IDF fighters could also go through or along the borders of Turkey (a friendly country) or Syria (a nonfriendly country), or a combination thereof, pushing flight routes of about 1,200 miles.

Secrecy would be a problem, too. While Israel has good operational security -- witness how much is still unknown about the Syrian raid -- an airstrike would require an armada of fighter, tanker, airborne early warning and electronic intelligence aircraft, which would light up radars across the region.

Even an uncoordinated, surprise Israeli air raid would likely quickly be known to others, especially the U.S., which "owns" the airspace in the Middle East and the Persian Gulf with its vast array of land, sea and air platforms and sensors. (Considering the geography, the possibility of unintended engagements between U.S. and Israeli forces almost eliminates the possibility of no notice being given to U.S. command authorities before a strike is launched.)

Many of the potential targets in the Iranian nuclear set, like the Natanz uranium enrichment facility, are also hardened, located near population centers and even buried as far down as 70 feet below ground. Plus, the Iranians are not likely to take this lying down. In addition to ground-based air defenses, including SA-5s and I-Hawk, the Iranian Air Force will throw an assortment of aging air assets at the Israelis, including MiG-29s, Su-24/25s, F-14s, F-4s, F-5s, F-7s and F-1s.

Moreover, an Israeli strike would severely complicate regional politics, especially for the U.S., which is (incorrectly) seen as Israel's handler. An attack by the Jewish state on a Muslim country, even troublesome Iran, would not be taken well at all in the region, especially on the "street." The situation would be further exacerbated, especially in some quarters of Iraq, if it were perceived -- or it were actually the case -- that the U.S. allowed the IDF to use parts of Iraqi airspace for, or turned a blind eye to, an attack on neighboring Iran.

Mission Impossible?

While these challenges to an IDF preventive strike against Iranian nuclear targets are significant, the mission, if embarked upon by Israel as a matter of national security, could be a success. The Israelis could advise the Americans of the strike in advance, allowing the two sides to deconflict their forces and providing a degree of freedom of movement in the gulf area for the IDF to operate if Washington supported the effort. Regional Arab states likely would not intervene, even if they became aware of the raid in progress. But they would protest vociferously after the strike, while privately breathing a sigh of relief, considering concerns surrounding an ascendant Iran.

Depending on the level of tactical engagement with the Iranians, the Israeli fighters, especially the F-15s, have the range to hit key targets. Precision-guided and penetration weapons such as JDAMs would likely be effective against hardened and buried targets. Nukes -- as some have suggested -- would not be necessary. But, the distances involved could limit the loiter time of Israeli fighters for dealing with emerging targets, especially those that might be involved in a counterstrike against Israel, such as Shahab-class road-mobile ballistic missiles. Of course, Israel's small fleet of cruise missile-capable, Dolphin-class diesel submarines, deployed to the Persian Gulf, could play an important role in a strike, especially against Bushehr in southern Iran. Israeli commandos could also play a role.

Persian Payback

Another issue that has to be taken into account by Israeli policymakers is that an IDF strike on Iran almost certainly would bring Iranian retaliation in a number of forms against Israel and its interests in the region -- and beyond. Israel could expect Iranian ballistic-missile attacks against large cities such as Haifa and Tel Aviv as well as conventional and terrorist attacks by Tehran's allies, Hezbollah or Hamas. And Syria could get into the act. (By association, U.S. interests could come into Iran's crosshairs, too.)

The next chapter of Iran's nuclear weapons program is not yet written, but Israeli policymakers and defense planners do not need to be reminded that a single nuclear weapon is enough to destroy the small Jewish state -- and its 7 million people. What is clear is that an Israeli strike on Iranian nuclear facilities would not be easy or ideal -- not to mention pregnant with plenty of potential negative consequences, for Israel, the U.S. and peace and stability in the Middle East more broadly. Indeed, while a strike might push back the Iranian nuclear program, it will not necessarily deter Tehran from continuing to pursue its atomic dreams: The Osirak raid served to steel Saddam's resolve to get the bomb, according to his former bomb makers.

But the green light for an attack is militarily doable if Israel perceives Tehran's Iranian nuclear weapons program might lead to Iranian President Mahmoud Ahmadinejad's notion that Israel must be "wiped off the map." The words of Israel's Menachem Begin government after the Osirak raid must still ring in the ears of Israel's policymakers today: "Under no circumstances will we allow an enemy to develop weapons of mass destruction against our people."

This year will likely bring more unhappy news about Iran's nuclear program as it cascades toward a weapons option. It will also be a fateful year for Israel, one that may require action against Iran -- no matter what the NIE says.

Peter Brookes is a Heritage Foundation senior fellow and former US deputy assistant secretary of defense.