In June 2013, two key factors created conditions more favorable for resolving the Iranian nuclear crisis–the devastating impact on Iran's economy of international sanctions, especially oil and banking sanctions, and the election as president of pragmatic regime insider Hassan Rouhani, who views an agreement on the nuclear issue as a crucial means of ending the sanctions, rebuilding Iran's economy, and overcoming its international isolation.

P5+1/EU negotiations with Rouhani's new team–supplemented and accelerated by secret U.S.-Iranian engagement–led to agreement in November 2013 on a Joint Plan of Action (JPA), a six-month interim agreement designed to provide the time and space needed to work out a final, comprehensive solution. The JPA halts further progress in all significant aspects of Iran's nuclear program, reverses progress in a few areas, and provides Iran modest relief from certain sanctions. It took effect on January 20, 2014, and has so far operated smoothly.

Intensive negotiations are now proceeding on the comprehensive agreement, with all parties seemingly committed to trying to reach agreement by the time the JPA expires on July 20. But key differences exist on the requirements of an acceptable deal, not just among negotiators at the table but also among key players outside the negotiations. Israeli officials and a number of members of Congress are demanding the elimination of key elements of Iran's nuclear program, and the Obama Administration and its supporters counter that several of those demands are neither achievable nor necessary for a sound agreement.

This paper recommends key requirements for an acceptable agreement–requirements designed to prevent Iran from having a rapid breakout capability and to deter a future Iranian decision to build nuclear weapons. A crucial issue in the negotiations, especially for the Iranians, is how the lifting of nuclear-related sanctions, as agreed in the JPA, will be phased. However, this paper focuses on the negotiating requirements of the P5+1, primarily the United States, and does not address the sanctions-lifting side of the negotiating equation.

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See full text at the Brookings Institution: Preventing a Nuclear-Armed Iran: Requirements for a Comprehensive Nuclear Agreement