Hassan Rouhani, Iran's newly elected president, will serve for four years. By the end of his term, Iran and the U.S. will either reach an agreement, or they will go to war.
Last March, Obama told an Israeli television station that it would take "over a year or so" for Iran to develop a nuclear weapon, the first time an American president stated a timeframe on the record. The dates coincide with a U.S. intelligence estimate during George W. Bush's administration: "sometime during the 2010-2015 time-frame."
These predictions are merely estimates and conjectures, but their accuracy is almost beside the point. What matters is that the U.S. and Israeli governments believe that Iran will have the capability to build a bomb while Hassan Rouhani is president.
Given the uncertainty, the U.S. and Israeli militaries will not wait until the last possible minute to attack Iran's nuclear facilities. They will wait until they see no alternative.
With Rouhani's election, the last remaining alternative is coming into focus. The Iranian regime shows no sign of collapsing, despite the economic sanctions and the popular protests of 2009. The technical failures and sabotage that had slowed uranium production have subsided. There is only one possible alternative remaining: a peace deal.
Some evidence suggests that Rouhani, if given the choice, would embrace such a deal. He has spoken of engaging the United States and rebuilding Iran's economy. Unfortunately, the choice will not be Rouhani's. He can sign no deal without the approval of Sayyed Ali Khamenei, Supreme Leader of Iran.
Khamenei has stated, "We don't want to build atomic weapons," but he has resisted all efforts to halt Iranian uranium production at great cost to the nation. And as with the intelligences forecasts, his actual intentions are almost beside the point. The U.S. and Israeli governments believe that he will direct Iran to produce a bomb, and they will attack if they believe there is no alternative.
And so, Iran's last chance is a peace deal, brokered by Rouhani and approved by Khamenei. The U.S. and Israel will grant Iran enough time for them to determine whether it's a genuine possibility. If they conclude that it is not--that there are no more alternatives to a nuclear Iran---they will go to war.