Iran's nuclear D-Day - Telegraph Amid all the jargon about centrifuges and uranium stockpiles, the central purpose of the Vienna talks on Iran's nuclear programme risks being overlooked. The goal of these sombre negotiations is nothing less than to remove the terrifying possibility of a nuclear-armed Iran by blocking every last route along which its rulers might lay their hands on the ultimate weapon. That is why these talks are so difficult. When John Kerry, the US Secretary of State, secured an interim agreement in Geneva last November, his only aim was to limit Iran's nuclear ambitions. Now Mr Kerry is no longer interested in freezing Iran's progress; he is after "rollback." Put bluntly, he wants Iran to start dismantling key elements of its nuclear programme, particularly its capacity to enrich uranium. In particular, Mr Kerry is believed to have asked Iran to sacrifice about 80 per cent of its 19,500 centrifuges and almost 90 per cent of its stockpile of low-enriched uranium. The combined effect would be to guarantee that if Iran ever decided to "break out" and build a nuclear bomb, its scientists would need about 12 months to produce the requisite quantity of weapons-grade uranium. Lest Mr Kerry's demands should seem unreasonable, remember that America previously demanded that Iran dismantle every centrifuge and abandon its entire enrichment capability. Now, the argument is only about how many of these machines Iran will retain. Moreover, America is willing to lift sanctions in return for a comprehensive agreement. So Mr Kerry has made an eminently fair offer: all that remains to be seen is whether Iran will have the wisdom to accept by today's deadline. If the answer turns out to be no, the whole rationale for negotiating with Iran will be open to question.