Exceptionalism is the view that one group is better than other groups and, by virtue of its alleged superiority, is not subject to the same constraints. Here we identify national exceptionalism in the responses made by political leaders in the United States and the United Kingdom to the covid-19 pandemic in early 2020. First, we observe that responses appealed to national values and national character and were marked by a denial of the severity of the situation. Second, we suggest an analogy between national exceptionalism and unrealistic optimism, i.e., people’s tendency to make rosier predictions about their future than is warranted by the evidence due to illusions of superiority and control. Finally, we argue that, at the national level, exceptionalism gave rise to an assumption of invulnerability that made for slow responses to the pandemic, and at the individual level, it served as a justification of people’s failures to adopt safety behaviors.