For over four decades, the United States and Iran have been enemies. Hostility is deeply ingrained within both states. In 2002, revelations about Iran’s covert nuclear program added a new layer to this relationship: how do you prevent a rival from acquiring nuclear weapons? For years, the United States deployed various coercive methods—sanctions, sabotage, military threats—to no avail. Then, during the Obama administration, Iran became the test case for engaging with ‘implacable’ adversaries on ‘intractable’ problems. Although the obstacles to success were formidable, in 2015, Iran, the United States, and the other P5+1 states announced the Joint Comprehensive Plan of Action (JCPOA). Under this agreement, Tehran accepted verifiable restrictions on its nuclear program in exchange for sanctions relief. Although the Iran Deal generated controversy within the United States, opposition did not weaken the administration’s resolve or derail the agreement’s implementation. Success, however, proved short-lived. In 2018, Donald Trump unilaterally withdrew the United States from the JCPOA. Today, Tehran is closer than ever to nuclear breakout and efforts to revive the JCPOA have stalled. On the one hand, this outcome may seem unsurprising. After all, the Obama administration was challenging a decades-old rivalry; scholars would anticipate narrative constraints. Yet the commitments that representatives make to other states generally do outlive their authors: pacta sunt servanda is no empty phrase. In short, both the agreement and undoing of the JCPOA defy expectations. This is especially because while many expected negotiations to fail, or Iran to cheat, it was American reversal that unravelled the JCPOA. In this thesis, I argue that the contradictory behaviour of successive administrations exposes a latent tension at the heart of state ontology—between collective identity and sovereign authority. Identifying these dual processes of state constitution can help scholars better understand the mechanics of narrative constraint: what allows stories to persist even when leaders defy them. To theorize what makes discursive boundaries operative and effective, I introduce the concept of narrative enforcement. I then illustrate my argument by demonstrating how the plural and continuous implication of Iran in the narration of U.S. identity enabled, even incentivized, an outcome that defied the systems-level imperatives of representative governance.