JCPOA: The Participants and International Law

On 14 July 2015, the Joint Comprehensive Plan of Action (JCPOA) was finalized, marking the end of long-term negotiations between the Ministry of Foreign Affairs of both Iran and the E3/EU+3. Only six days later, the United Nations Security Council askedall participants of JCPOA to fully implement the deal. It also adopted Resolution 2231 and terminated all previous resolutions.
However, despite all absolute commitments of the participants of JCPOA and contrary to theU.N. Security Council resolution, the U.S. overlooked the deal starting from the implementation day. Eventually,the current U.S. President, Donald Trump, announced on Tuesday, May 8, 2018, that he will withdraw the United States from the Iran nuclear deal.
Nevertheless, according to international law, JCPOA is not considered a bilateral agreement and so does not provide grounds for any participants to alter their position asthey wish. Rather, it is a multilateral political comprehension endorsed by the UNSC and has a binding nature deriving from Resolution 2231. This resolution reiterates full and holistic implementation of JCPOA and prohibits any violation regardingthe deal.
The main question of the present paperis about the legal nature of the JCPOA. The approach of the UNSC towards JCPOA and the responsibilities of the participants and other U.N. member states toward JCPOA are other questions thatare worth considering from an international perspective.