In the US, there's a lot riding on a nuclear deal with Iran: the President's legacy, relations with Israel — a major issue in next year's election. In Iran, the possible lifting of sanctions has created towering expectations, especially among the young. Support is "steadfast and unequivocal," according to a recent survey by the International Campaign for Human Rights in Iran. But hopes for an unfettered economy, political reform and doors opening to the rest of the world are tempered by uncertainty. We talk with insiders. Meantime, what about Iran's Arab neighbors? For them, a deal could make a powerful competitor more dangerous than ever.