Illustration by Eric Timothy Carlson
Illustration by Eric Timothy Carlson

There has been a lot of talk about Iran making a sudden dash for the bomb. The fear is that, with its thousands of gas centrifuges and its tons of enriched uranium, Iran might be able to make a bomb’s worth of nuclear fuel before the U.S. or any other country could intervene to stop it.

In a speech in September at the United Nations, Israeli Prime Minister Benjamin Netanyahu went so far as to display a bomb diagram, on which he drew a red line showing when the dash might occur. He said it could be as early as this spring.

It is surprising that this version of events has gained such currency, because it isn’t likely to happen. Iran, in fact, doesn’t seem to be in a hurry. It is playing a longer game, all the more menacing because it is more likely to succeed.

Iran’s goal is to build a nuclear arsenal at an acceptable cost. To achieve that, Iran must avoid any drastic step that would trigger a war. In a shootout with the U.S., the ayatollahs would risk their survival -- a large cost indeed.

Iranian leaders have stayed just beneath the line of intolerable provocation. Of course, they must also keep the pain from sanctions low enough to avoid revolt. They are succeeding there as well. So their strategy is working.

Multiple Bombs

Its success is only one reason that Iran probably won’t race for a bomb anytime soon. A second reason should be fairly obvious: No country wants only one bomb. That is especially true of the type of bomb Iran has been trying to develop. It employs the principle of implosion, and would have to be tested. The U.S. was obliged to test its implosion bomb in 1945 before dropping “Fat Man” on Nagasaki, Japan.

Iran, too, would be obliged to test, to find out whether its design worked, and to let the rest of the world know it worked. Otherwise, there would be no effect of nuclear deterrence, which is the reason for getting the bomb in the first place. Thus, a sprint to produce one bomb’s worth of fuel -- a possibility that has spilled a small torrent of ink estimating how long it would take -- would cross the finish line with mainly test data.

And the activity would probably be detected. The director of U.S. intelligence, James Clapper, assured a congressional committee in March that Iran couldn’t divert material and make a weapon-worth of uranium “before this activity is discovered.” By “material,” Clapper meant the uranium Iran has already enriched. Most of it is “low-enriched,” meaning two-thirds of the way to weapon-grade. A small amount is “medium-enriched,” meaning 90 percent of the way.

To make a dash now, Iran would have to start with enriched material; to start with natural, unenriched uranium would take so long as to be impractical. But there is a catch: All the enriched uranium is regularly checked by UN inspectors. Within a few weeks at most, they would probably detect its diversion.

The result would be a perfect storm, politically. Governments would be under tremendous pressure to act. Israel, the U.S. and Europe couldn’t afford not to. Iran would be in flagrant breach of its Nuclear Nonproliferation Treaty obligations, which require continuous inspection of enriched uranium and forbid its use for any but peaceful ends. Iran could face the very war it had been trying to avoid.

This war could start before the dash succeeded. To produce bomb-grade uranium, Iran would have to enrich its stockpile further. That means passing it again through its centrifuges. Unluckily for Iran, yet luckily for just about everybody else, its present generation of centrifuges is grossly inefficient.

Iran’s largest known enrichment site is near Natanz, about 160 miles south of Tehran. It is home to some 9,000 rapidly spinning centrifuge machines. How long would it take these machines to raise Iran’s uranium stockpile to weapon-grade?

Uranium Supply

Only a small amount of work would be needed, in theory, if it started with the medium-enriched uranium. The minimum time, assuming everything went perfectly, could be as low as a few weeks. But there is a big problem. Iran has only enough of this material for one bomb. To fuel even a small arsenal of five bombs, Iran would need to amass far more, which would take three years at its present rate of production.

Could Iran start with its larger stock of low-enriched uranium? It has enough now to fuel five to six bombs, a plausible number for a beginner’s arsenal. But it would take at least eight months to raise that much to weapon-grade. Such a production run, of course, won’t happen. It wouldn’t be a sprint or even a jog. It would be a crawl, in plain view. Long before Iran could fuel even five bombs, precision-guided munitions could be streaking down.

Instead, Iran is playing the longer game. It can follow the example of Israel, India and Pakistan, which came to the bomb late, yet got true arsenals without armed conflict and are now accepted as nuclear powers.

The Iranians are experimenting with better centrifuges, reported to enrich uranium three to five times faster. Several hundred of these machines are at Natanz already, and Iran predicts that 3,000 will be installed “in the near future.”

Enrichment is also increasing. There is room at Natanz for tens of thousands of additional centrifuges, and Iran could triple the number operating at its fortified Fordo plant. Sometime next year, Iran will amass enough low-enriched uranium to fuel seven bombs and, if it activates its idle capacity at Fordo, enough medium-enriched uranium to fuel five more. A dozen bombs would be a credible nuclear force.

So roughly two years from now, we could see a new situation. Iran could have a hefty stockpile of medium-enriched uranium; it could be operating several thousands of potent new centrifuges; it could be operating thousands more of its old centrifuges; throughout the Islamic Republic, scores of workshops would be creating centrifuges at locations unknown to international inspectors. It may have entered at last the “zone of immunity” the Israelis have been warning about, meaning that Iran’s power to make nuclear weapons would no longer be vulnerable to air attack.

Comfort Zone

That status is what Iran seems to be striving for. What Israel dreads as a danger zone, Iran would welcome as a comfort zone. If Iran fed its new centrifuges with its new stock of medium-enriched uranium, it could shave enrichment times to the bone. Instead of taking a few months to fuel five bombs, the theoretical time would shrink to a few weeks.

This is bound to create an aura of inevitability. Iran can reasonably hope that when its program is fully mature, the world will decide that an aerial attack won’t be adequate, that all-out war will cost too much, and that “containment” will be the better way to go.

The U.S. and its allies have found no way to counter this strategy. They have imposed sanctions, yet the sanctions haven’t stopped nuclear progress. They have warned of military action. Iran seems not to believe it. The U.S. and its allies have urged negotiations, but this misreads the needs of the long game. Iran must push ahead. How can it accept the UN’s demand that it stop enriching uranium? If it did, it could never perfect its new centrifuges, and would be frozen at a level where it could never reach an arsenal. Iran’s nuclear argosy would be stuck on a reef.

Instead, the U.S. is stuck. Iran is doing nothing sufficient to create a crisis. It tiptoes forward, builds its potential every day, claims a right to enrich uranium, deals with sanctions, and strings out negotiations. “No breakthrough but also no breakdown,” was what a U.S. official called it after the most recent round of talks.

To sever the deadlock, the U.S. must change its game. It must carry out what it says is its policy on Iran. The Barack Obama administration claims to have a policy of “prevention,” that is, to stop Iran from getting the bomb. This is different from “containment,” which tries to manage a nuclear threat after it arises. The administration even says it will prevent the capacity to build a bomb -- an earlier phase in development -- rather than wait until Iran is only a screw-turn short of success.

Small Arsenal

There is only one way to apply such a policy: to define the point where Iran’s ability to make a small arsenal comes into being and to state what will be done to prevent that point from being reached. In other words, red lines. Plus statements of what will happen when they are crossed.

For example, the U.S. could declare a limit on the amount of enriched uranium Iran would be allowed to accumulate (the excess would be sent abroad) or declare a limit on the number of centrifuges Iran could deploy (new or old). And the consequences could be a progression. First, more severe sanctions, and then military steps such as interdiction of oil shipments, a blockade of ports or even an air attack. At each step Iran could limit the harm by limiting its program.

None of this seems to fit the administration’s playbook, yet without it, the U.S. has no way to build political support for taking action. This last point is vital. If prevention is really the policy, then force has to be an option. Yet the U.S. can’t attack Iran out of the blue. The American public would have to be prepared, as would U.S. allies. The U.S. government would have to remind everyone that the UN has condemned Iran for violating the Nuclear Nonproliferation Treaty, that Iran thereby lost any right to enrich uranium, that the UN has called on Iran to cease enrichment, and that Iran hasn’t complied.

To this could be added Iran’s unflagging support for terrorist groups, its supply of parts for roadside bombs in Iraq that have killed U.S. troops, and its outrageous violations of human rights. All of these could and would be cited in support of red lines, if prevention were really the policy.

Instead, Uncle Sam has maintained a mild demeanor, intended to nurture negotiations. They have gone nowhere for years. It is clear why. Iran sees all too acutely that the U.S. isn’t ready to set red lines, and is even further from using force. None of the political groundwork has been done, or is likely to be done.

Without it, threats aren’t credible. Thus, Iran sees no impediment to its long game. It is working well, and, unless something changes, it will give Iran the bomb.

(Gary Milhollin is executive editor of, a website on Iranian weapons programs that is published by the Wisconsin Project on Nuclear Arms Control. The opinions expressed are his own.)

To contact the writer of this article: Gary Milhollin at

To contact the editor responsible for this article: Katy Roberts at