Why did Great Britain remain neutral during the American Civil War? Although several historical arguments have been put forth, few studies have explicitly used International Relations (IR) theories to understand this decision. Synthesising a discursive approach with an ontological security interpretation, I propose an alternative framework for understanding security-seeking behaviour and threats to identity. I assess the impact Abraham Lincoln's Emancipation Proclamation had upon the interventionist debates in Great Britain. I argue that the Proclamation reframed interventionist debates, thus (re)engendering the British anxiety over slavery and removing intervention as a viable policy. I conclude by proposing several issues relevant to using an ontological security interpretation in future IR studies.