If the process of turning uranium into a gas were not disrupted, the uranium would still need to be enriched. Iran's enrichment facilities most likely use old technology (provided by Pakistan) that is notoriously temperamental. "In our industry," Wolfsthal says, "we call these 'self-disassembling' machines." Enrichment takes place in long cascades of centrifuges; powerful magnets hold each centrifuge in place while it spins at high speeds to separate the fissile uranium. The magnets are prone to mishap. "If the [electrical] current powering the magnets fluctuates," Wolfsthal points out, "you can send the centrifuge flying out of its case, careening across the room like a bowling pin, and knocking out the rest of the centrifuge cascades." Such a fluctuation could be set off in the part of the power grid supplying the plant. (Like many other countries, Iran has a grid known to be unreliable at times and vulnerable to attack.) Similarly, letting a small amount of air into the vacuum-sealed centrifuges could destroy many of them and set the enrichment program back years.
Building and operating Iran's nuclear program also requires the expertise of scientists and technicians. Intimidating or assassinating key scientists has forestalled weapons development in other countries. In the late 1950s Egypt launched a ballistic-missile program with the help of German scientists, many of whom were former Nazis. In July of 1962 President Gamal Abdel Nasser unveiled two new test missiles at a military parade, bragging that they could hit targets "south of Beirut." Mossad quickly responded with Operation Damocles, an intimidation campaign targeting the German scientists. One scientist was killed in September, two months after the parade, and in the following months the scientists' families were threatened directly. In November several letter bombs addressed to the scientists were sent to the rocket facilities in Egypt; one of them killed five Egyptians. (This part of the campaign was rumored to have been called "post-mortem.") Soon all the German scientists had left Egypt—and its missile program—behind. Without them the program withered.
Iran's indigenous scientific capabilities today are much greater than Egypt's were in the 1960s, so presumably it would be much harder to eliminate them—but perhaps not impossible. A recent report written by several former senior Israeli military and intelligence officials under the leadership of Dr. Louis Beres, an American professor of international relations and international law at Purdue, advises Prime Minister Sharon to adopt a "doctrine of pre-emption" against Iran's nuclear program, and provides a menu of covert and overt options for crippling it. Prominent among them is "decapitation"—a swift covert strike against either the "enemy leadership elites" or the program's scientists and engineers. Several experts are skeptical that such a plan could succeed. But Beres believes that the logistical hurdles are surmountable. "The question," he says, "is to what extent this would be regarded as barbarous, uncivilized, and destabilizing by the international community."
Covert action alone is unlikely to solve the problem of Iranian nuclear ambitions. After all, the cloak-and- dagger efforts to sabotage the Osirak reactor bought only a couple of years' delay before Israel launched a military strike. But some of Iran's nuclear facilities (like Natanz) are not as close to being fully operational as Osirak was in 1981, and in some ways its program is more vulnerable. And permanent solutions look hard to come by today.
Meanwhile, both the United States and Israel are deeply concerned that Iran, with a nuclear shield to defend it, might seek to expand its influence as it did in the years immediately following the Islamic revolution, when it used groups like Hizbollah and Palestinian Islamic Jihad to carry out large-scale terrorist attacks in the region. The Israelis worry that Iran would resume attacks against their country through these terrorist groups after a ten-year period of relative quiet.
Ashton Carter, a former assistant secretary of defense, says that he would be "surprised and disappointed" if a covert campaign wasn't already under way. Conducted skillfully, Carter argues, such a campaign might not merely forestall Iranian progress toward a bomb; it might also sow doubt, causing Iranian officials to question whether their equipment actually worked and whether the people involved in the program could be trusted. By reducing the Iranians' confidence in their ability to produce nuclear weapons, it might even prompt Iran to consider abandoning its nuclear program, in return for the carrots it has so far spurned at the negotiating table.