IN the annals of role reversal, the switch by the United Nations' atomic sleuths in Vienna and the American intelligence community has been striking. Having long taken a back seat to the Bush administration in publicly challenging Iran's nuclear program, the global inspectors last week moved into the driver's seat, demanding that Tehran come clean on any progress it has made toward building a bomb. What gives? Quite simply, and to some extent literally, the Americans have handed over the wheel on the confrontation with Iran. After challenging Iran's atomic efforts with everything from diplomatic crusades to shows of military force, the Americans backed off late last year, based on a new intelligence finding that Tehran had suspended work in late 2003 on the design of nuclear arms. Now, in the waning days of President Bush's second term, it would be difficult — politically, diplomatically and militarily— for them to try to press for a new confrontation. But early this year, Washington also turned over a trove of its own intelligence to the atomic investigators in Vienna, who put it together with clues gathered from many foreign capitals and findings from their own long years of inquiries. On the basis of that combination of new and old evidence, over the last few months, the inspectors of the International Atomic Energy Agency (IAEA) have come to worry that Iran — before suspending its work nearly five years ago — may have made real progress toward designing a deadly weapon. Last week, the issue crystallized publicly when the inspectors issued an uncharacteristically blunt demand for more information from Tehran and, even more uncharacteristically, disclosed the existence of 18 secretly-obtained documents that suggest Tehran had high interest in designing a nuclear weapon before the program was suspended. The presentation posed a central question and gave it urgency: Just how far did Tehran get toward designing a bomb before the program was halted? That question could transform the debate over what to do about Iran, particularly because it is being posed now by an international agency that retains high credibility overseas, something the Bush administration lost long ago. In their report last week, the Vienna-based investigators called the evidence of the early warhead work “a matter of serious concern,” and said that uncovering the real story “is critical to an assessment of the nature of Iran's past and present nuclear program.” As they have for years, the Iranians repeated their assertion that there was no such armaments program — that their nuclear program is intended solely for peaceful purposes like generating electricity. But the inspectors showed their impatience with such responses, and with the lack of cooperation from Iran in general, by discussing the 18 suspicious documents. They also revealed that an Iranian scientist once displayed photos of the world's first nuclear blast, in 1945, alongside equations for calculating its destructive power. Why the emphasis now on sins Iran may have committed in the past? Wasn't the finding that warhead design stopped in 2003 reassuring enough? No, say nuclear experts inside and outside the international agency. Candor about Iran's progress in designing a weapon matters because Tehran's scientists continue to move forward on a related front. They are learning how to make uranium fuel. And if they already have a good warhead design in hand, the lack of fuel may be the one thing standing between them and the ability to make a bomb. “Fuel is usually the limiting factor,” said Robert S. Norris, author of “Racing for the Bomb,” a history of the Manhattan Project. “The other stuff is relatively easy.” He noted that the United States managed to design the Hiroshima bomb by 1944 but could make its needed uranium fuel only after years of industrial labor that culminated in 1945. “As soon as they had enough — bingo — it went into a design they were so sure would work that they never bothered to test it,” Dr. Norris said. Last week, the Institute for Science and International Security, a private group in Washington that tracks the spread of nuclear weapons, said its analysis of the new inspectors' report showed that the Iranians are steadily overcoming problems and enriching uranium fuel at faster rates. American intelligence agencies say the earliest Iran could have enough fuel for a nuclear warhead is 2009, but 2010 to 2015 is a more likely time frame. Any estimate in that range could put the potential for a crisis squarely on the agenda of the next American president. The documents cited by the inspectors in Vienna carry dates like 1984, 1987, 1989, 1993, 1998, 2002, 2003 and 2004. Many are in Persian. One describes experiments on a sphere of detonators like the array that could trigger an atomic explosion. Another tells of tests of 500 detonators, and yet another bears a schematic diagram of a shaft a quarter-mile deep and six miles from a firing point — a good setup, experts say, for the underground detonation of a nuclear weapon. The inspectors say one reason they want more information from Iran is to test the Iranian assertion that the documents are forgeries or repetitions of false charges. In fact, these sleuths are considered quite skilled in fraud detection. In early 2003, on the eve of the American invasion of Iraq, their agency was the one that exposed as false American claims that Saddam Hussein had sought uranium in Niger. This time, the agency is putting on Iran the onus of disproving the documents' authenticity. The Iranians “lied, obfuscated and didn't tell us for 20 years what they were doing,” said a senior official close to the agency, who spoke on the condition of anonymity under normal diplomatic rules. “What's the intention? That's the question.” The American finding last December that Iran suspended its weapon-design work in 2003 created a classic case of a glass that could be seen as either half full or half empty. The American intelligence community, in the finding, judged that “the program probably was halted in response to international pressure” and drew the inference that “Iran may be more vulnerable to influence on the issue than we judged previously.” It did not mention the possibility that now seems to concern the international inspectors — that Iran had perhaps made enough progress that it could afford to slow down or stop. Senior officials who oversaw preparation of the American intelligence report say Iran's weapon-design work, with the right fuel, might have progressed enough by 2003 to make a bomb comparable to the five-ton blunderbuss dropped on Hiroshima. But that does not mean they have a workable design for the most frightening kind of bomb in today's world — one miniaturized to about one ton so it can sit atop a missile, which is much faster and harder to stop than any plane. Such a weapon, say military strategists, can change a region's balance of power without ever being fired. And that is why determining the extent of Iran's progress on weapons design is so important to the atomic investigators in Vienna. Iran is working hard to develop a family of long-range missiles, the Shahab, Persian for shooting star. The Shahab 3, Iran's most-advanced missile, can reach European capitals, and in their report the atomic investigators cited a document whose title, translated from Persian, reads: “Implementation of Mass Properties Requirements of Shahab-3 Missile Warhead With New Payload.” Officials in Vienna doubt that Iran will quickly answer their questions about possible work on miniaturized nuclear arms. So, they say, it could take months to come to definitive conclusions about the true nature of the Iranian program. In the meantime, the Institute for Science and International Security has concluded that Iran will find it hard to deny convincingly that it sought the secret of making nuclear arms. “These documents,” the institute concluded, “make a powerful case.” The question remains, though: How far did Iran get? – New York Times __
