Abstract: The so-called Iran nuclear agreement, officially known as the Joint Comprehensive plan of Action, is an agreement between Iran and the five permanent members of the UN Security Council as well as Germany and the EU to ensure that Iran’s nuclear program will be exclusively peaceful. Praised as an historic diplomatic achievement that resolved a decade-long crisis, the 2015 agreement is distinctive in its comprehensive provisions and innovative solutions to various legal and technical issues. However, US President Donald Trump’s controversial decision to withdraw the US from the agreement in May 2018 has put its future in peril. This paper attempts to analyze the legal aspects of the US’ decision to withdraw from the Iran nuclear agreement with special reference to the currently on-going US-North Korea deal for the complete denuclearization of the Korean Peninsula. In the course of this study, special attention is given to the lessons learned from the Iran nuclear agreement.