Americans on Sunday received what appeared to be mixed messages about Iran's nuclear status from two top U.S. defense officials. Asked on CNN's State of the Nation whether Tehran has enough fissile material to make a bomb, Joint Chiefs of Staff Chairman Admiral Mike Mullen answered, "Yes, I believe they do." Headlines around the world screamed that a top U.S. official was warning that Iran now had the nuclear material to assemble a weapon. But Mullen, through a spokesman, quickly corrected that impression by emphasizing that he was referring to low-enriched uranium which, in its current state, can fuel a nuclear reactor but cannot create a weapon. Defense Secretary Robert Gates further clarified matters on NBC's Meet the Press, saying that Iran was "not close to a stockpile, they're not close to a weapon at this point, and so there is some time."
The distinction drawn by Mullen and Gates cuts to the heart of the nuclear standoff with Iran and is critical to the urgency with which the issue is placed on the desk of President Barack Obama. The U.S. intelligence community and the International Atomic Energy Agency (IAEA) do not suspect that Iran is developing a nuclear weapon; they're concerned that Iran is developing the means to build a nuclear weapon by using a legitimate nuclear-energy program to assemble the key elements of a weapons program. Those elements include a uranium-enrichment capability that would allow Iran to create bomb material should it opt to break out of the close scrutiny to which its program is currently subject by the IAEA. (See pictures of the legacy of Iran's revolution.)
Last month, Obama mentioned Iran's "development of a nuclear weapon" at a news conference before later correcting himself to specify that he was referring to Iran's pursuit of the "capability" to produce such a weapon. That's in line with the assessment offered by his director of National Intelligence, Admiral Dennis Blair, in a Feb. 9 briefing to the Senate Intelligence Committee: "Although we do not know whether Iran currently intends to develop nuclear weapons, we assess Tehran at a minimum is keeping open the option to develop them."
Mullen's answer on CNN referred to the almost 800 kg of low-enriched uranium that has passed through the centrifuges at Iran's Natanz nuclear facility, which could be reprocessed to create enough bomb-grade material for a single crude nuclear device. Nuclear weapons require plutonium, or uranium enriched above 90%, whereas Iran's stockpile is enriched to a level of 3.7%, well within the limit allowed for reactor fuel under the Nuclear Nonproliferation Treaty (to which Iran continues to adhere, despite the dispute over its activities). Its low-enriched uranium stocks are under seal by the IAEA, and enrichment activities are closely monitored by international inspectors, who have certified that no material has been diverted for any possible covert bomb program.
In order to turn its stockpile of low-enriched uranium into bomb fuel, Iran would have to unambiguously declare its intentions by kicking out the inspectors and breaking from the treaty. Only then could it reconfigure its centrifuge cascades and reprocess the material to higher grades of enrichment, which would likely take a number of months. And the single very crude, very large nuclear device that would result too large to be delivered by missile or by fighter aircraft would not constitute a credible strategic nuclear capability. The power to project nuclear force would require the development and production of at least a handful of bombs, miniaturized to fit inside warheads and on missiles that Iran currently doesn't have. Iran would probably still be a couple of years away from that capability if it made the fateful decision to kick out the inspectors now a decision that would probably provoke an emergency reaction from the U.S. and its allies. (See the top 10 Ahmadinejad-isms.)
Hence the assessment from the Pentagon: Iran is making steady progress in assembling a nuclear infrastructure that would put nuclear weapons within reach, but it is not close to achieving nuclear-weapons status. While Tehran's leaders are committed to a nuclear program that would give it the means to build weapons, they have not made the political decision to move beyond assembling and start developing nuclear weapons. Stopping Iran from building nukes is a singular priority of the Obama Administration, a challenge that it plans to pursue through what the President has called "tough, direct diplomacy." But the question of how long the U.S. has to pursue a diplomatic outcome before Iran crosses the nuclear-weapons threshold will obviously shape the Administration's approach to engaging Iran. The message from the Pentagon appears to be that Iran's nuclear progress is cause for deep concern, but there's no need for panic.