Barring a “catastrophic development,” Middle East Newsline reports, President Bush has decided not to attack Iran. An administration source explains that Washington deems Iran’s cooperation “needed for a withdrawal [of American forces] from Iraq.”

If correct, this implies the Jewish state stands alone against a regime that threatens to “wipe Israel off the map” and is building the nuclear weapons to do so. Israeli leaders are hinting that their patience is running out; Deputy Prime Minister Shaul Mofaz just warned that “diplomatic efforts should bear results by the end of 2007.”

Can the Israel Defense Force in fact disrupt Iran’s nuclear program?

Top-secret analyses from intelligence agencies normally reply to such a question. But talented outsiders, using open sources, can also try their hand. Whitney Raas and Austin Long studied this problem at the Massachusetts Institute of Technology and published their impressive analysis, “Osirak Redux? Assessing Israeli Capabilities to Destroy Iranian Nuclear Facilities,” in the journal International Security.

Ms. Raas and Mr. Long focus exclusively on feasibility, not political desirability or strategic ramifications. Were the Israeli national command to decide to damage the Iranian infrastructure, could its forces accomplish this mission? The authors consider five components of a successful strike:

• Intelligence: To impede the production of fissile material requires incapacitating only three facilities of Iran’s nuclear infrastructure. In ascending order of importance, these are the heavy water plant and plutonium production reactors under construction at Arak, a uranium conversion facility in Isfahan, and a uranium enrichment facility at Natanz. Destroying the Natanz facility, in particular, they note, “is critical to impeding Iran’s progress toward nuclearization.”

• Ordnance: To damage all three facilities with reasonable confidence requires — given their size, their being underground, the weapons available to the Israeli forces, and other factors — twenty-four 5,000-lb. weapons and twenty-four 2,000-lb. weapons.

• Platforms: Noting the “odd amalgamation of technologies” available to the Iranians and the limitations of their fighter planes and ground defenses to stand up to the high-tech Israeli air force, Ms. Raas and Mr. Long calculate that the IDF needs a relatively small strike package of 25 F–15Is and 25 F–16Is.

• Routes: Israeli jets can reach their targets via three paths: Turkey to the north, Jordan and Iraq in the middle, or Saudi Arabia to the south. In terms of fuel and cargo, the distances in all three cases are manageable.

• Defense forces: Rather than predict the outcome of an Israeli-Iranian confrontation, the authors calculate how many Israeli planes would have to reach their three targets for the operation to succeed. They figure 24 planes must reach Natanz, six to Isfahan, and five to Arak, or 35 altogether. Turned around, that means the Iranian defenders minimally must stop 16 of 50 planes, or one-third of the strike force. The authors consider this attrition rate “considerable” for Natanz and “almost unimaginable” for the other two targets.

In all, Ms. Raas and Mr. Long find that the relentless modernization of Israel’s air force gives it “the capability to destroy even well-hardened targets in Iran with some degree of confidence.” Comparing an Iranian operation to Israel’s 1981 attack on Iraq’s Osirak nuclear reactor, which was a complete success, they find that this one “would appear to be no more risky” than the earlier one.

The great question mark hanging over the operation, one that the authors do not speculate about, is whether any of the Turkish, Jordanian, American, or Saudi governments would acquiesce to Israeli penetration of their air spaces. (Iraq, recall, is under American control.) Unless the Israelis win advance permission to cross these territories, their jets might have to fight their way to Iran. More than any other factor, this one imperils the entire project. (The IDF could reduce this problem by flying along borders, for example, the Turkey-Syria one, permitting both countries en route to claim that Israeli planes were in the other fellow’s air space.)

That Israeli forces have “a reasonable chance of success” unilaterally to destroy key Iranian nuclear facilities could help deter Tehran from proceeding with its weapons program. The Raas-Long study, therefore, makes a diplomatic deal more likely. Its results deserve the widest possible dissemination.

Mr. Pipes, the director of the Middle East Forum, taught for two years at the U.S. Naval War College.