The Nuclear Question
Developing an indigenous nuclear-weapons program with all the necessary infrastructure, technical knowledge, and material requires an enormous investment. The Iranian regime has developed its nuclear capabilities over the course of several decades, although the existence of the program in its current form was discovered only within the last decade. Iran has already demonstrated its ability to enrich uranium, the most difficult of the three primary elements of a nuclear-weapons program. (The other two are the weaponization of fissile material for a payload and the development of a delivery system.) It has also demonstrated the ability to advance its technical knowledge, as evident in its production of uranium enriched up to 20 percent. This is especially significant because the challenge of getting from 20 percent to weapons-grade requires only a small fraction of the effort required to enrich up to 20 percent.85 The breakout time required for Iran to produce fuel for a nuclear weapon has also been reduced considerably as a result. In a detailed technical analysis for the Nonproliferation Policy Education Center, Gregory S. Jones finds that Iran could now produce enough fuel for a nuclear weapon using its current stock of enriched uranium in roughly two months; the same task would have required two to four years according to Jones’s estimates in 2008.86 Recent International Atomic Energy Agency (IAEA) assessments have also highlighted evidence of Iran’s experimentation and work on nuclear payloads, high explosives development, and the redesign of its medium-range ballistic missiles (MRBMs) to house a nuclear warhead.87 The agency’s November 2011 report indicated that inspectors had corroborated information regarding Iran’s weaponization work with the accounts of several IAEA member states and its own efforts.88
Despite reports in 2010 and 2011 suggesting that Iran’s enrichment program had been set back significantly by the Stuxnet software virus, the most recent IAEA assessments indicate that Iran’s enrichment program has recovered. Yukiya Amano, head of the IAEA, rejected outright the assessment earlier this year that technical problems have disrupted Iran’s enrichment program.89 Its current stockpile of low-enriched uranium is sufficient to fuel four nuclear weapons once it is enriched to weapons-grade levels.90 These developments demonstrate that the Iranian nuclear program has expanded and progressed despite technical hurdles, malfunctions, the recent sanctions regime, and a chorus of denunciations; Iran is moving rapidly toward acquiring a nuclear-weapons capability.
Historically, states that acquire the capability to develop nuclear weapons expand the size of their nuclear arsenal over time. The first eight nuclear countries all increased their arsenal sizes by varying degrees, particularly within the first decade of possessing their first weapons.
These states now possess anywhere from several dozen to more than one thousand warheads. Although opinions as to what the Iranian regime might decide to do in building its arsenal abound, it is important to recognize that there is not a single historical case in which a country has gone nuclear and capped the size of its arsenal to one, two, or a handful of bombs.91 There is no basis in historical precedent or in the nature of the current Iranian regime to assert that Iran would defy this trend. A nuclear Iran can reasonably be expected to expand its quantitative nuclear force over time—in either a deployed state, a preconstruction form, or a combination—by amassing a requisite stockpile of bomb-grade material.
How large of an arsenal could Iran initially field? The primary resource input Iran acquired for its uranium enrichment program was a 531-ton supply of yellowcake from South Africa. Over time, the Iranian program has converted a significant portion of this stockpile to uranium hexafluoride (UF6), the feedstock used in centrifuges for enrichment. The IAEA confirmed in its May 2011 report that Iran has produced 371 tons of UF6. This stockpile could be used to fuel a sizeable nuclear-weapons arsenal. Estimates of the amount of UF6 required to produce fuel, or highly enriched uranium (HEU), for one nuclear weapon vary depending on efficiency rates. A conservative estimate for such an amount is ten tons.92 Thus, Iran’s existing stockpile of UF6 provides enough material to produce HEU for at least thirty-seven nuclear weapons. The projected size of the arsenal would not necessarily be limited to this estimate. Iran may have depleted much of the yellowcake it acquired from South Africa, but it possesses domestic uranium mines and is currently involved in mining these deposits outside the purview of IAEA inspectors. Its domestic-mining production could be supplemented through the import of yellowcake uranium from external suppliers.93
It is a reasonable presumption that Iran’s current capacity, supplemented by the development of its own mining industry and foreign resources, would facilitate the growth of a nuclear-weapons arsenal approaching, and possibly surpassing, that of the other regional nuclear powers. Importantly for the United States and the question of deterrence, Iran stands on the brink of developing not just a single weapon but also a modest breakout capability for a more robust arsenal that would seem to fit both the practice of previous new nuclear states and provide a survivable deterrent. That is, Iran could acquire a large enough force to raise serious questions in the minds of US military planners that they could eliminate Iran’s nuclear retaliatory options in a single raid or rapid-strike campaign. On the current trajectory, the US-Iran nuclear balance is likely to resemble traditional forms of the nuclear balance of terror.
Neither the nuclear policies of past US presidents nor of the Obama administration has accounted for this—or similar developments with other current nuclear or soon-to-be-nuclear states—in reckoning the needs of US nuclear forces. It is perhaps the most durable legacy of the Cold War that the United States remains almost solely focused on the balance with Russia and the arms-control legacy that has come to frame the issue.
The administration’s 2010 Nuclear Posture Review reflects what has been a growing US schizophrenia on the emerging nuclear world. The review describes the current weapon with chilling accuracy:
Concerns have grown in recent years that we are approaching a nuclear tipping point—that unless today’s dangerous trends are arrested and reversed, before very long we will be living in a world with a steadily growing number of nuclear-armed states and an increasing likelihood of terrorists getting their hands on nuclear weapons.94
At the same time, the review made clear that the administration intends to respond to these new facts almost entirely through arms control and diplomacy rather than reconsidering the need for a newer, more flexible and larger US nuclear force.95 Almost simultaneously, it concluded the “New START” deal with Russia that reduced the number of deployed US nuclear warheads from 2,200 to 1,500 and hopes to conclude deeper reductions. The president prefers to trust in an international nonproliferation regime rather than traditional deterrence through sufficient nuclear strength.
For the United States, the nuclear question must now include an element of the involvement question. That is, in the emerging multipolar nuclear world—where Iran is hardly the only likely new nuclear state, the balance among larger powers is shifting significantly with the growth of the Chinese and Indian arsenals, and the capabilities of “small” nuclear states like Pakistan are increasing—the number of tasks for the US nuclear deterrent force is multiplying, as is ambiguity about the deterrent calculus in each case. These new facts raise fundamental new questions about the nature of US extended deterrence and even more about the assurance of US allies facing new threats.
As John S. Foster Jr. and Keith B. Payne have pointed out, some threats can be countered only by nuclear weapons. They write, “Nuclear weapons may be the only means available for promptly destroying hard and deeply buried targets, achieving prompt war termination, preventing an adversary from marching on and annihilating civilian centers, or for possibly eliminating nuclear or biological threats arrayed against the United States and [its] allies.”96
General Kevin Chilton, former commander of US Strategic Command, seconded the point in congressional testimony, saying, “The nuclear weapon has a deterrent factor that far exceeds a conventional threat.?
??97 It is impossible to say with clarity or precision what US nuclear-force requirements for a nuclear deterrent to Iran might be, but that is exactly the point. Decisions about US nuclear capabilities remain on a Cold War trajectory, without analysis of an appropriate posture for today and tomorrow.98