Defining Our Red Lines

In a column in the October 7 Washington Post, I argued that "red lines" with respect to Iran's nuclear program, far from leading us automatically to war, are designed to facilitate diplomacy and prevent conflict. As Iran makes continued progress toward a nuclear weapons capability -- and according to a new report by the Institute for Science and International Security, it is now as little as 2-4 months away from having sufficient weapons-grade uranium (WGU) for a single bomb -- defining our red lines takes on increasing importance.

For all of its bluster, the Iranian regime has proceeded carefully to reach this point, expanding its nuclear capabilities while avoiding full-blown conflict with the West. The final stage of its nuclear drive will pose a significant challenge to this strategy, however, as any outright lunge for a nuclear weapon is likely to draw a devastating response. Iran could take any of several approaches to this last leg, from throwing caution to the wind and making a mad dash in the open, to proceeding entirely clandestinely. For this reason, we need not just one but several red lines, closing off all routes available to Iran for achieving a nuclear weapons capability.

The route to an Iranian nuclear weapons capability that receives the most attention is the most straightforward, but perhaps the riskiest for Iran -- a dash using Iran's declared enrichment sites and uranium stockpiles. It is this route which both Israeli PM Netanyahu and ISIS warned about recently. Their worry is straightforward -- as Iran expands its nuclear capacity and increases its stockpile of 19.75 percent uranium, its breakout time diminishes even further, perhaps to the point where a military response could not be mounted quickly enough to prevent Iran from producing and secreting away a bomb's worth of WGU or more.

It is this worry that led Netanyahu to declare his redline -- Iran stockpiling sufficient 19.75 percent uranium to, if further enriched, produce a single nuclear weapon. It is important to recognize, however, that Iran can dial its production of enriched uranium forward or back and thus control the pace of its confrontation with the West -- forward, by increasing the number of centrifuges enriching; back, by sending 19.75 percent uranium to be converted into another form unsuitable for further enrichment, such as fuel plates for the Tehran Research Reactor (TRR). Iran in the past has done just this -- moving quickly ahead during lulls in negotiations, and then resuming international talks to diffuse the resulting threats and pressure. 

Iran could also proceed in a nonlinear manner that skirts this redline -- for example, by producing small batches of higher-enriched uranium without having first stockpiled a single bomb's worth of 19.75 percent uranium. A prominent Iranian legislator has already asserted, for example, that Iran would begin producing 60 percent enriched uranium for use in nuclear submarines. Iran could also simply continue amassing LEU while perfecting more efficient centrifuges, diminishing its breakout time for a future weapons dash.

Rather than a dash in the open, which would give the U.S. and Israel time and opportunity to mount a military response, Iran may prefer to attempt to limit the IAEA's access to its program and achieve a nuclear weapons capability out of sight of international inspectors. This would be in keeping with Iran's history of nuclear deception and subterfuge.

Iran could, of course, simply expel IAEA inspectors and hope that the US does not respond, but this would be a risky proposition. Far more likely would be incremental steps which reduce the IAEA's access or place obstacles in front of inspectors, in order to divert some portion of Iran's uranium stockpile (e.g. the 19.75 percent uranium removed from Fordow for conversion to fuel plates) to a heretofore undisclosed enrichment site, reduce the certainty with which the inspectors are able to account for Iranian activities at declared enrichment sites, or lengthen the time between inspections to a degree that would not permit a breakout to be detected in a timely fashion.

Because such steps might appear modest to a casual observer, Iran may believe that the U.S. would find it difficult to rally an international response to them. Iran has already reduced its cooperation with the IAEA over the last few years. Alarmingly, as detailed in a recent Washington Post article, Iran's far-fetched accusations that IAEA inspectors have engaged in acts of sabotage may represent an effort to establish a pretext to reduce that cooperation further.

There are further routes still that Iran could take to break out and achieve a nuclear weapons capability. It could attempt not simply to divert declared uranium stockpiles to a undisclosed enrichment facility, but to create an entirely parallel, covert uranium supply, conversion, and enrichment chain using the expertise and procurement networks it has gained from its disclosed program. It could also seek to acquire a nuclear weapon, or simply the fuel for one, from an existing nuclear power such as North Korea, with which it already cooperates extensively. Iran would face serious obstacles in either scenario, but neither can be discounted entirely.

By understanding Iran's pathways for completing the final stage of its nuclear drive, the U.S. and our allies can devise red lines -- whether private or publicly announced -- which fence off those pathways. These red lines should take into account not only Iran's stockpile of enriched uranium, but also the level to which it enriches any uranium, the access it affords IAEA inspectors, the expansion of its centrifuge program and other weapons-applicable technologies, as well as any covert efforts to build additional nuclear sites or acquire nuclear materials abroad.

Perhaps more importantly, however, such an analysis of Iran's pathways to a weapon can help policymakers strengthen existing tools and devise new approaches -- from better intelligence collection, to more focused efforts to enforce sanctions and stymie Iranian nuclear procurement efforts, to joint warnings from the U.N. or other multilateral bodies -- to ensure that Iran never approaches those red lines in the first place.

Michael Singh is managing director of The Washington Institute.