As a contribution to the book collection 'The Politics of Replacement: Demographic Fears, Conspiracy Theories, and Race Wars,’ Jack Wilson and Louie Dean Valencia analyse the manifesto and weapons of the individual who perpetrated the 2019 Christchurch mosque shootings. Discussing the so-called ‘Great Replacement’ conspiracy theory and the user culture of the platform 4chan – both of which are associated with the individual – they argue that the historical references written on the individual's gun can be situated within historical-national discourses on the topic of ‘Western Civilisation’ in his home country, Australia. Such discourses predate the aforementioned conspiracy theory and platform, and thus the authors argue that situating the individual therein may offer a more comprehensive understanding of their ideological motivations.