Expect a big rebound in the Iranian currency, the rial, and in stock markets as expectations grow of the easing of sanctions and foreign investors arriving in Tehran …
… while in Washington, a deal could spark a fierce political battle. It would avert new congressional sanctions for a while at least, as Obama would retain enough Democratic support to wield a veto. But Congress would be expected to back a law demanding Obama submit the deal to a vote …
… in New York, at the UN security council, preparations would be made to codify the deal as a resolution, with few obstacles to passage …
… while negotiators pressed on to fill in the blanks in the deal to hit a June deadline for a comprehensive detailed agreement. If this were agreed and the UN resolution passed, a range of sanctions would be lifted. The UN and EU would take a staggered series of measures to ease sanctions, as well as the suspension of some US sanctions by presidential decree. Iran would prepare to ship out some of its stock of enriched uranium, while dismantling or disconnecting thousands of centrifuges. A new deal with the International Atomic Energy Agency would be signed, allowing tighter inspections. The Iranian economy would benefit from a significant opening to foreign investment …
… a diplomatic dividend would depend on the degree of backlash by hardliners in Tehran and Washington. Moves could include reciprocal US and Iranian visits to each other's capitals, with talks on restoring permanent representation. There could be more open meetings to coordinate combating Islamic State in Iraq, where Iranian and US interests broadly align, though cooperation over Syria would be likely to take much more time.
Expect a fall in the value of the rial and the Iranian stock market, and a rally in the price of oil. The Iranian parliament, the Majlis, would be likely to pass legislation paving the way for ending restrictions on Iran's nuclear programme …
… while Congress would be likely to pass new sanctions legislation, leading to counter-measures by the Majlis, escalating nuclear activity. The White House would state clearly the military options for containing Iranian activity …
… and Israel would have to weigh up conflicting advice on whether to launch air strikes on Iranian nuclear facilities, and whether such strikes would be effective. The negotiating group of the permanent five members of the UN security council plus Germany would be likely to splinter over new US sanctions and threats of military action …
… the tit-for-tat escalation of sanctions and nuclear activity could well trigger military action from Israel within months, quite possibly with US support. Any air strikes could lead Iran to withdraw from the nuclear non-proliferation treaty, and throw out IAEA inspectors …
… while hopes for joint diplomatic demarches on Iraq and Syria would be damaged, possibly irreparably, by the new confrontational mood.