Iran nuclear talks: why the diplomats deserve a little more time They have extended for the second time a temporary deal which was agreed a year ago, promised a so-called "framework" agreement by March, which would formalise the areas of consensus, and a final, "comprehensive" agreement by July, which would fill in the thorniest details. This is a worryingly long timeline, because it allows opponents of diplomacy in Washington and Tehran plenty of time to undermine their governments. It would have been better to commit to a framework agreement before the new year, and a final settlement by the Spring. Nevertheless, an extension is the right choice. First, the gaps are clearly narrowing. To give one example, a senior Iranian official insisted as recently as July that "Iran needs at least 50,000 centrifuges and not 49,999. We will not compromise on that. Predictably, though, Iran has done exactly that; its diplomats now speak of retaining just 8,000 or so centrifuges, out of the approximately 20,000 that Iran has installed at present. This still isn't enough for Western nations, who insist that Iran must be a year away from producing sufficient enriched uranium for one bomb, but the two sides are getting closer, with the US reportedly increasing its offer to 4,500 centrifuges. It is easy to imagine the two sides compromising around the 5-6,000 mark, something that would leave ample time to respond diplomatically and militarily to any Iranian attempt at 'breaking out' for a bomb. Second, contrary to what the hawks will claim, Iran does not gain by "running down the clock." The terms of the now-extended agreement explicitly forbid Iran from, among other things, adding new enrichment capacity or accumulating more enriched uranium. Iran is obliged to convert any surplus into a form that's much harder to use for weapons purposes. Other aspects of Iran's programme, notably enrichment to the higher and more dangerous level of 20 per cent, are forbidden altogether. Without an extension, Iran would be free of all such constraints. It is hard to see how that would be an improvement. One exception, admittedly, is Iranian research and development in the area of newer, more sophisticated, and more efficient centrifuges. While Iran isn't allowed to install such centrifuges to enrich uranium, if it uses the next seven months to hone this technology further, then this would be a legitimate area of concern. However, it would have been politically infeasible to tweak the extension to take this into account, because Iran would have demanded concessions of its own, potentially unravelling the whole thing. Third, Iran enjoys no net financial gain through this extension. Iran will be permitted to access $700 million per month of its frozen oil revenue held abroad. This sounds like a lot, until you consider that the vast and complex array of US, European, and UN sanctions are costing Iran somewhere between $1.8 and $5 billion per month. Iran is economically bleeding, and the idea that they're just stringing us along simply doesn't make sense. Even with this extension, negotiators on both sides face formidable obstacles. In January, a Republican-controlled Congress, bent on new sanctions, will bed in. President Obama's ability to veto their efforts successfully will depend on whether he can persuade moderate Republicans and Democrats that diplomacy is making serious progress. Iran's President Hassan Rouhani faces different but equally serious constraints, with hardliners ready to pounce on any suggestion of compromise. These domestic hurdles will get worse, not better, over time. Both leaders might lose their grip on the issue by next summer, and relying on the whole seven-month extension would be foolish. They must not let the window slide shut.