If the main merit of The Internationalists is to shed light, in a powerful and convincing way, on the transformative power of rules, the role of institutions – and in particular of the United Nations and its collective security system centred around the activity of the Security Council – does not come out of the book as clearly as it might. It is submitted that the decision to concentrate upon the rule – the prohibition to use force – while limiting the attention paid to the institution – the United Nations and its collective security system – is not without consequence, particularly given the strict link existing, in the common perception, between the rule and the institution. This brief comment will focus on certain ambivalences emerging from the book about the contribution of the United Nations, as a peace-enforcing organisation, to fostering the emergence of a New World Order, as well as its continuing relevance for preserving the effectiveness of the principle on non-use of force.