David Sanger, Senior Fellow at the Belfer Center and the National Security Correspondent for the New York Times, writes in the New York Times on the shifting course of American diplomacy with Iran during the negotiations on Iran's nuclear program. From the earliest meetings facilitated by the Sultan of Oman with Iranian officials, to the final hours of the tense negotiations in Vienna, he describes the shifting priorities and views of the American and Iranian diplomatic teams, and how compromises on sanctions and centrifuges allowed the deal to come together.