“Imperial overstretch” and the role played by related ideational issues derived from particular liberal tenets and the US’ belief in its “manifest destiny” to lead the world, have been regularly cited as explanations for why the US’ ambitious project to transform the world in the post-Cold War era failed. In this article I argue that these analyses have overlooked a crucial causal factor which also impelled the US to undertake its ultimately doomed project: hope. I demonstrate that analyses of hope’s influence have found that while hope can exert a positive influence, it can also – if irrational – induce self-destructive behaviour. During the period of unipolarity, the US repeatedly advanced teleological visions of a bright future for humanity routinely infused with the language of hope. I demonstrate that hope was, however, more than just a discursive device; it was itself a catalyst for the US’ actions. I argue that a confluence of factors at the end of the Cold War aligned to impel the rapid emergence of a particular variant of hope – defined as ‘wilful hope’ – which inspired the US to act as it did. I demonstrate how this disposition was evident in the rhetoric employed by both Presidents Bill Clinton and George W. Bush but also – more importantly – in the strategies they each implemented. Ultimately, this disposition played a crucial – though not exclusive – role in undermining international support for US leadership and precipitating the end of ‘the unipolar moment’.