There is one fact on which everyone concerned with Iran's apparent drive toward nuclear capability agrees: Launching air and missile strikes against the country is a very risky strategic move. The questions are whether the risk of inaction is greater, and whether such a strike could delay or disrupt Iran's plans enough to be worth the cost.

Analysts from both the U.S. and Israel agree that Iran's program cannot be stopped. They contend that if the aggressive, but smaller, Israeli air force attacks alone, development could be slowed by about two years. If the U.S. launched a raid, with its larger inventory of specialized weapons, long-range bombers and cruise missiles, the program could be derailed for five years, and perhaps as many as 10.

An unknown in the calculus of an attack is the effectiveness of Syria's recently updated air-defense surveillance and networked intelligence-gathering in detecting and tracking an incoming raid on Iran. Syria has radar sites in Lebanon's Bekaa Valley as well as on its own territory. Both countries have extensive, updated air-defense equipment provided by Russian companies.

“The Syrians took a large step during the last 3-4 years,” says Brig. Gen. Amikam Norkin, chief of Israeli air force operations. “They put all their money into two things—air defenses and [tactical] rockets and missiles. We need to find and attack the missiles because we need to keep flying from our bases, even if there is a rocket attack.”

In addition, regardless of who disables Syrian missiles, Israel will have to prepare its area defenses and work better with its intelligence systems.

“We have to be ready for the SA-24, 22 and 17,” Norkin says. Those are advanced, Russian-made, surface-to-air missiles, known to NATO as the Grinch, Greyhound and Grizzly. “You have to deal with all the layers. Cyber- and integrated air defenses in Syria and Lebanon will present something new. What the U.S. Air Force is dealing with, we are dealing with.”

Attacks that do not involve bombs but rather use cyberweapons (a joint U.S. and Israeli effort) and assassination of Iranian scientists (supported by Iranian nationals) have slowed the program over the last several years, though they have not stopped it.

Estimates of the time necessary to enrich enough uranium to construct a bomb range from months to as much as a year, say Israeli analysts. U.S. officials contend that the Iranians have not made the decision to build bombs and the deadline for action against Iran's bomb program is more than a year.

“The U.S. strategy is to launch a military attack only if they see the Iranians actually breaking out [with enrichment of uranium beyond 20%],” says Amos Yadlin, a former Israeli fighter pilot and head of military intelligence who is now director of Tel Aviv University's Institute for National Security Studies (INSS). “Unfortunately, I think most of the estimates in Washington are wrong.”

Given that Iran has shown no willingness to abandon its uranium-enrichment program throughout a series of fruitless negotiations, only the timing of a military strike by the U.S. or Israel—followed by a series of retaliatory attacks by Iran—appears uncertain. The U.S. elections and the crisis in Syria are providing distractions, but both countries say Iran will not be allowed to create a bomb.

“It was [Akbar Hashemi] Rafsanjani, the president of Iran [from 1989-1997], who in 2001 said that Israel is a one-bomb country, while Iran can absorb two or three bombs [and still survive],” Yadlin says. “The real threat is a nuclear weapon exploding over Tel Aviv. I served under three prime ministers, and each asked me if Iran would launch a nuclear weapon against Israel. As chief of intelligence, I said the chances are 90% [that it will not]. But with a nuclear weapon, that 10% is a lot.”

At least one U.S. expert, though, former U.S. Air Force Gen. and Central Intelligence Agency director Michael Hayden, says the Israeli air force alone cannot neutralize the Iranian bomb development capability.

“I do not underestimate the Israeli talent, but geometry and physics tell us that Iran's nuclear program would pose a difficult challenge to any military,” he said in an interview with Israel's Haaretz daily newspaper last year.

The crux of his argument is that a single raid cannot inflict enough damage. The targets “will have to be revisited, which only the U.S. Air Force would be able to do” with its stealth bombers and larger, earth-penetrating weapons, Hayden says. He also contends that the Iranians will not be able to begin work on a nuclear weapon until 2013 or 2014, which makes it possible to delay action.

Any air force contemplating an attack on Iran with manned aircraft will have to field some well-trained aircrews with the ability to fly complicated routes to evade detection and concentrated air defenses. To that end, during the last 15 years, the Israeli air force has trained to fly long distances and meet unfamiliar opposition.

“Israel is very small, with long borders and a complicated neighborhood,” Morkin says. “The Israeli air force [first] flew across the Atlantic [in 2002] to Davis-Monthan [AFB, Ariz.,] and Red Flag [at Nellis AFB, Nev.]. Then we started working with others like Italy, Britain and Germany, and this summer we flew to Bulgaria, engaged its air force and flew back without landing. We learned from the U.S. Air force that we needed to be better at flying long missions.”

The Israeli air force is aware of its weak points. “We need more unmanned aerial vehicles and tankers,” Norkin says. “We're going to keep developing [new] UAVs. Tankers have a very small chance” of being funded. But even if Israel does not have the resources for a large aircraft such as the KC-767 tankers, there may be other more affordable solutions. In the meantime, the aircraft are able to conduct fighter-to-fighter, buddy-tanking.

Both the stateless militant group Hezbollah, mainly located in Southern Lebanon, and Iran's government have warned that a strike on Iran's nuclear sites by Israel or the U.S. would trigger extensive retaliation against both countries, including U.S. bases in the region that are within range of Iran's conventional missiles.

“The [only] difference between the U.S. and Israel [in concept of operations] is in the timing,” Yadlin says. “This has to do with the U.S. Air Force having many more assets and operational capabilities than the Israeli air force.”

Israeli military planners do not delude themselves that an attack is a solution to Iran's nuclear threat. There is still uncertainty and debate among them and government officials about the Iranian nuclear threat.

In early September, Prime Minister Benjamin Netanyahu canceled a meeting of his security cabinet because of leaks about its deliberations. The cancellation followed a report in the Yediot Aharonot newspaper that there is no consensus among intelligence agencies about when Israel's ability to damage Iran's nuclear program would no longer be effective. A participant reportedly said briefings by the Mossad, Shin Bet and military intelligence agencies presented information that was “very troubling, but still not frightening.”