This study offers a glimpse into how the transatlantic relationship between the European Union (the EU) and the United States of America (the U.S.) has developed during the last three presidential administrations, including the Trump administration. To do this, the study has developed a frame- work on transatlantic convergence, divergence, and drift, which it uses to analyses similarities and differences within the different parties’ discourses on the Iranian nuclear weapons program. The study concludes that while there has been some divergence with all three U.S administrations, how- ever there has been far more convergence with the Bush and Obama administration than with the Trump administration. Moreover, this study argues that Trump administration represents in some ways a ’transatlantic drift’, since the parties have opposing views on the Iran deal (JCPOA) and cherish widely different fundamental security values.