The Nuclear Maginot Line

French Minister of War Andre Maginot became infamous among military strategists for his fixation on a single route of attack that led to a fatal neglect of alternatives. Seeking to block a German invasion along the primary East-West axis, Maginot constructed an impregnable line of fortifications in the 1930s. He succeeded in preventing the attack he most feared, but when German panzers outflanked that line and rolled through Belgium in 1940, their attack from the rear led to France’s surrender in just six weeks.

In concentrating so much of their attention on imposing constraints on Iran’s known nuclear facilities at Natanz, Fordow, and Arak, are the United States and its five negotiating partners (collectively known as the P5+1) at risk of creating a nuclear Maginot line?

In the world of business, when a firm wants a product, the first question it asks is: Make or buy? Quite often, it is the latter choice: to buy. In highly competitive markets—for example, next-generation personal computing devices—Apple and Google also ask the question: Overt or covert? While occasionally they publicize in advance the features of a product they will bring to market in the year ahead, more often (for example, in the case of the iPad), they develop the product in the secrecy of their own labs—and only then announce what they have done.

We should ask the same kinds of questions of Iran’s nuclear program: Is the Islamic Republic more likely to make or buy? Overtly or covertly? In the current negotiations with Iran, is the United States so focused on limiting one avenue to a nuclear bomb that we have neglected other possible routes? To clarify this question, consider the table below.

First, if in the next several years, we discover that Iran has a nuclear bomb, along which of the four paths will it have succeeded?

Take a look at the figure below. Then fill in the boxes, putting the number “1” in the quadrant you judge to be Iran’s most likely path for acquiring the bomb and then the numbers “2,” “3” or ”4” for what you estimate will be the second, third, and fourth most likely routes. When we went through the same exercise with several dozen experts in Washington and at Harvard, answers were split between “make/covert” and “make/overt,” with “buy/covert” in third place.

Figure 1

Now look at the second figure below. Reflecting on where the P5+1 governments have invested their attention, energy, and effort to prevent Iran from achieving its nuclear ambitions, fill in the quadrants, this time putting “1” in the box that is consuming most of the attention, and “2,” “3,” and “4” for the others. Here, the same informal poll yielded a consensus around the “make/overt” option.

Figure 2

It is understandable, of course, that with negotiations ongoing between Iran and the P5+1 about specific constraints on nuclear activities at Iran’s overt, declared sites, the public debate focuses almost exclusively on the make/overt path. To this point, the interim agreement reached in November essentially halts Iran’s nuclear advance at the 9,400 centrifuges currently spinning and a stockpile of six to seven bombs’ worth of low-enriched uranium (LEU) and requires Iran to dilute or convert to oxide nearly one bomb’s worth of 20 percent enriched uranium produced prior to the agreement. Now, the negotiations over constraints that could be extended for a decade or beyond are focused on transforming the heavy-water reactor at Arak to prevent it from producing plutonium for a bomb; capping the number and capability of centrifuges used to produce enriched uranium; reducing stockpiles of enriched uranium; and introducing a host of monitoring and safeguard mechanisms. These limits, summed up in a single measurement, seek to verifiably and significantly extend the “breakout time”—the length of time it would take for Iran to produce its first bomb’s worth of highly enriched uranium at these facilities.

The broader question, however, is this: How effective will these constraints be in meeting the bottom-line objective, namely, preventing Iran from acquiring a bomb? Maginot’s success in blocking a direct attack along the path he fortified did not excuse his failure to defend his country.

We hope that negotiators will succeed in reaching an agreement. If they do, members of Congress, the larger policy community and America’s allies will debate the adequacy of what is achieved at the negotiating table as they consider the repeal or waiver of legislated sanctions. But it is also critical for everyone to appreciate that, to assess the true contribution of any agreement to the central objective—no Iranian bomb—we must consider the agreement’s impact on every possible path toward a nuclear weapon. Indeed, as the P5+1 consider where to spend their limited leverage in negotiating a combination of constraints on Iran’s overt program and transparency about Iran’s nuclear activities, it is essential for them to ask how specific terms in a negotiated agreement advance, or alternatively retard, efforts to stop Iran along all such paths.

Our purpose is to challenge the analytic community to pause and examine the larger questions as carefully as it has analyzed constraints on Iran’s declared nuclear facilities. To jump-start that debate, we offer the best five conclusions we have reached so far:

First, the tighter the constraints and transparency on Iran’s overt nuclear program, the higher the relative likelihood Iran will try to obtain a nuclear bomb through other means. Reducing Iran’s capacity at its overt enrichment facilities, undoubtedly a key requirement for the agreement, would free up equipment and personnel that Iran could use elsewhere, including a potential covert facility.

Second, a hybrid path to a bomb could divert LEU or 20 percent enriched uranium from its declared facilities overnight to a covert enrichment facility to produce high-enriched uranium (HEU) before the site would be discovered. An agreement that requires Iran to eliminate stockpiles of LEU or 20 percent enriched uranium by converting it directly to fuel rods is the only way to reduce this risk.

Third, a second hybrid option would be to buy fissile material from abroad and then make a weapon at a covert site. This troubling scenario highlights the need to address potential cooperation between North Korea and Iran. No one should forget that North Korea sold a nuclear reactor to Syria, which would have by today produced enough plutonium for Syria’s first nuclear bomb had it not been destroyed by an attack, reportedly by Israel, in 2007. A negotiated agreement should expressly prohibit any import of nuclear-related material or technology from North Korea.

Fourth, although the current negotiations are focused primarily on curbing Iran’s progress at overt facilities, they also offer an opportunity to try to stymie covert (make, buy or hybrid) paths, to increase the P5+1’s confidence that such paths would be quickly detected and to provide the international community with grounds to react quickly if violations are discovered.

In thinking about specific terms to include in an agreement, the P5+1 should start by requiring that Iran ratify and implement the IAEA Additional Protocol, which grants the International Atomic Energy Agency greater authority to inspect all aspects of a country’s nuclear fuel cycle; and adhere to the modified Code 3.1, which requires countries to provide design information for all nuclear-related facilities before construction begins. The parties could then demand a full accounting and transparency of Iran’s: (1) centrifuges, in particular where all key components have been manufactured and stored, how many, and what types; (2) uranium mining and milling and stocks of yellowcake; (3) procurement of sensitive materials (i.e., “maraging” or high-strength steel, advanced carbon fiber); and (4) select dual-use items, such as vacuum equipment and motor drives used in enrichment. In addition, strengthening the IAEA’s authority to demand surprise inspections of undeclared sites that it suspects may house nuclear-weapon related activity would reduce risks of covert options.

Moreover, the P5+1 could allow (and require) Iran to meet its verified nuclear-related purchasing needs through legitimate channels, while making clear that any illicit trade violates the agreement; monitor Iran’s nuclear research and development (R&D) efforts; impose a verifiable cap on Iran’s production of advanced centrifuges; collaborate on peaceful nuclear R&D projects to keep Iran’s cadre of nuclear scientists and engineers meaningfully employed and engaged; secure an Iranian commitment not to conduct covert nuclear-related activities—and not to buy nuclear material from abroad or collaborate with countries that are not parties to the Nuclear Non-proliferation Treaty; require that Iran ratify the Comprehensive Nuclear Test Ban Treaty and refrain from constructing an underground nuclear test site; and invite Iran to participate in future nuclear security summits.

Fifth, as a complement to a negotiated agreement, and to ensure that it will be enforced, the P5+1 could seek a U.N. Security Council resolution that authorizes members to take action if Iran is caught covertly making or buying nuclear material.

In seeking to reach a comprehensive nuclear deal that prevents Iran from acquiring a nuclear weapon, we must keep in mind that success in the battle to block the overt path does not guarantee victory in ensuring that Iran does not acquire a bomb. Clearly, some government officials are aware of this fact. But in the final phase of negotiations, when trade-offs will have to be made among competing demands, those making hard choices should repeatedly consider how specific terms of the deal impact all paths to a nuclear weapon.