Even for NPT-compliant member states, enrichment is not a sacrosanct right. The traditional position of the US government, at least, is that the NPT does not grant a right to enrich. Most NPT members obtain their nuclear fuel from a handful of suppliers.

To reward a country that was declared in non-compliance with the NPT with an industrial-sized nuclear-enrichment programme effectively creates a new benchmark. Henceforth, every nation on earth will expect at the very least to be treated like Iran, even if it chooses to initially pursue a nuclear programme in violation of the NPT. The enrichment capacity that will eventually be granted to Tehran will be the baseline for demands by other regional powers such as Egypt, Turkey and Saudi Arabia, to have their own enrichment programmes.

Third, Iran has broken the growing tide of sanctions that was crippling its economy and deprived Western governments of a critical component of their strategy. Iran's reward, though reversible if talks were to collapse, is double. Not only has it won a victory on enrichment even before a deal is done, but it has denied the West the critical sanction leverage that it previously wielded. By entering an interim agreement that deprives the West of the power to enact new sanctions, Iran can slowly erode their power without making meaningful concessions. Iran and the Obama Administration seem to agree on one point — that the only alternative to the current negotiating framework is war. With such a choice, Western governments will negotiate until Judgment Day rather than reimpose sanctions and risk war. Iran's negotiating stance will therefore improve over time.

Fourth, Iran has removed its ballistic missile programme and its past military activities linked to the nuclear programme from the negotiations. It has already managed to sweep its missile programme under the carpet — although that is equally forbidden under UN Chapter VII resolutions. The six world powers have also agreed that lack of progress by the IAEA in its efforts to get Iranian answers on the possible military dimensions of its nuclear programme will not hamper a deal. Yet there is no chance a final agreement can put together a satisfactory implementation and verification mechanism unless Iran's past clandestine activities are fully disclosed, investigated and accounted for. Any agreement that sidesteps such issues will inevitably only be able to verify Iranian good behaviour in known nuclear facilities — but not be able to detect any potential misbehaviour in clandestine installations. Given Iran's history of deception, it is a recipe for disaster.

And fifth, Iran has eroded Western positions on key components of any future agreement, ensuring that, should these gains be consolidated into a final deal, Iran's pathway to a nuclear bomb will be at most delayed, but not impeded. It looks as if a deal will eventually tie Tehran's hands, ever so gently, for ten years at most. For a US President in his second term, even such a deal looks like a historic legacy. For a zealous regime driven by imperial ambitions and a religious sense of history, ten years is a blink of an eye and a promise that, within a decade, Iran will resume its dash to the bomb unimpeded.