Joint Comprehensive Plan of Action (JCPOA) was a final conclusion of the long term negotiations of  the Ministres of Foreign Affairs of 5+1 and the I.R. of Iran which was signed  in 14 July 2015 ( 23 Tir 1394).
Following the JCPOA and after just six days, the United Nations Security Council adopted the resolution 2231 in 20 July 2015 ( 29Tir 1394), which according to, all previous resolutions of the United Nations Security Council terminated and Security Council asked all parties of the JCPOA to implement the action plan completly.
Disloyalty of the US, perticularly at the begining of the presidential term of Donald Trump have shown lack of good faith in implementation of   international commitments pertaining to the JCPOA. Furthermore, since the Res2231 reiterates necessity of full- implementation of the DOC and prohibits any weakining action, as EU and Russia believe, expressions of president Tump and some actions of USCongress not only may weaken the JCPOA but also contradict it’s spirit, and binding UNSC Res- 2231.