Two years after his election, President Hassan Rouhani of Iran is about to go down in history as a leader who defused an intense and bitter conflict that could have led to a military attack on Iran. A nuclear deal that the majority of Iranians hope will bring an end to the isolation of Iran, much needed relief from international sanctions, and a new chapter in U.S.-Iran relations is now in sight. If other enemy countries have faced each other on the battlefield and ultimately managed to work out their differences, why is it impossible for Iran and the United States to do the latter?