Iran deal is not the best but it's better than we had Building to continue: Iran's heavy water plant near Arak. After decades of a brittle relationship between Iran and the West, especially Washington, all sides had refused to get excited about any agreement on Tehran's nuclear program. But there it was, news of a landmark deal in a 3am tweet by a senior European diplomat in Geneva. And in subsequent hours it was cemented in, in a statement and comments by US President Barack Obama and a global cast of negotiators or their principals, all of them needing to convince domestic and international constituencies that this was more than just a pause in Iran's nuclear program in which to keep talking. But it is fragile - and ripe for sabotage. After almost 10 years of headbutting and threats or demands about war, the Western powers and Iran have agreed to a six-month freeze in the program. The deal is being described as a confidence-building measure, perhaps to achieve something more lasting and permanent in the next round. Iran is to stop enriching uranium beyond 5 per cent and will dismantle the links between its centrifuges. And its stockpile of 20 per cent enriched uranium, just short of weapons grade, is to be diluted or reduced to a less militarily useful oxide state. In exchange Iran gets access to about $US7 billion of its own funds that have been snap frozen in the international banking system by Western sanctions. It is not a lot. It accounts for just over 1 per cent of the national budget of $US600 billion. But the deal sounds good - yes? The critics were in high dudgeon when Catherine Ashton, the European Union's chief foreign policy official, flashed her tweet. But they would be, wouldn't they? Viewed from Washington, buying six months before returning to threats of war against Iran is a valuable respite. But Washington is not Tel Aviv or Riyadh. And to that extent, this interim agreement could be too late because the Middle East already is locked in its own regional arms race. Israel, which refuses to sign the nuclear nonproliferation treaty, has stockpiled a nuclear arsenal in a program it developed with the same secrecy that it accuses Iran of adopting to achieve a bomb by stealth. And while Israel is estimated to have hundreds of devices, Tehran is estimated to be close to enough fuel for just a couple. Now Saudi Arabia is threatening to go nuclear - as a hedge against the other two. From the Israeli and Saudi perspectives, it is wrong to treat Tehran as a negotiating partner. They reason that Iran has to be walloped. And if the wallops so far have not been sufficient, there need to be more of them - and harder. Of course there were compromises. Iran agreed to ban producing fuel for, or to start up, its new heavy water reactor near Arak - but it refused to halt construction. And it has agreed to more intense - in some cases daily - international inspections. On the issue of a right to enrich uranium, the parties agreed to disagree. Tehran can continue enriching without a formal blessing from the world. Given the tortured past 30-odd years of the Tehran-Washington relationship, the deal will be a better springboard to a more constructive agreement than would an acrimonious collapse of the Geneva talks. Watch now as hardliners on all sides try to undermine it. It remains to be seen whether Obama can keep Israel's allies in Congress at bay, at the same time as he tests a new openness to the West and a willingness by Iran's new President, Hassan Rouhani, to negotiate.