Following a decade of international court creation during the 1990s, the 21st century has witnessed a widespread backlash against many international courts from dissatisfied member governments. By and large, studies of international court backlash have taken an optimistic tack, noting that most international courts have survived episodes of backlash intact or – in the case of the paralyzed Appellate Body (AB) of the World Trade Organization (WTO) – are likely to do so after a temporary period of backlash-induced slumber. In this context, this paper analyzes the United States’ successful effort to paralyze the AB, to derive lessons from this striking case of backlash against one of the world’s most active and independent international courts. Undertaken in the context of a collective research project on “Reversing Delegation,” this account of the AB crisis is organized in five parts, examining in turn the empirical history of delegation, politicization, de-delegation, counter-mobilization, and the (interim) outcome of this episode during the Trump administration and the early months of the Biden Administration. First, I demonstrate that the creation of the AB was a classic instance of delegation of third-party dispute-settlement power, and that the AB quickly emerged as an active, and possibly activist, agent of international trade liberalization. Second, I explore the roots of US politicization of the AB, noting that dissatisfaction with AB jurisprudence preceded the Trump administration, although I argue that Trump’s politicization of the AB was more far-reaching, and more public, than that of his predecessors. Third, I examine the Trump administration’s stepped-up effort to use its veto power to paralyze the AB, an act of at least temporary de facto de-delegation. Fourth, I examine the pushback from the many other WTO members that sought to defend the AB: although these efforts have been widespread and consistent, I argue, they failed, over a period of years, to budge the US position. Fifth and finally, I analyze the outcome, thus far, of the US campaign, arguing that, by the standards of domestic curb-curbing activities, it has been remarkably successful, not only in temporarily paralyzing the AB but also in demonstrating that such efforts are allowed and even facilitated by WTO rules, planting the seeds for a potentially significant recontracting with the AB or its successor, and exerting a chilling effect on future AB judges following the end of the current crisis.