For many years, the United Nations Security Council expressed its concerns about the proliferation risks presented by the Iranian nuclear program, doing so in the context of its primary responsibility under the Charter of the United Nations for the maintenance of international peace and security. With the intent to resolve its concerns, the Security Council adopted Resolution 2231 on July 20, 2015. The Resolution endorsed the Joint Comprehensive Plan of Action (JCPOA) that had been concluded on July 14, 2015, by China, France, Germany, the Russian Federation, the United Kingdom, the United States, the European Union, and Iran (the E3/EU + 3). Resolution 2231 and the JCPOA are closely intertwined. Their implementation will result in strict limits on Iran’s ability to produce weapongrade nuclear material. On-site verification and monitoring of these limits by the International Atomic Energy Agency (IAEA) will provide assurance that Iran is observing them. Resolution 2231 and the JCPOA also provide for a step-by-step removal of sanctions imposed on Iran for its past failure to resolve concerns about its nuclear program. Past concerns about “possible military dimensions” to Iran’s nuclear program, while neither misplaced nor necessarily fully assuaged, were put aside, being outweighed by the prospect that the JCPOA offers, “a comprehensive, long-term and proper solution to the Iranian nuclear issue.”