Liberalism is a defining feature of modern democracy, illustrated by the prevalence of the term ‘liberal democracy’ as a way to describe countries with free and fair elections, rule of law and protected civil liberties. However, liberalism – when discussed within the realm of IR theory – has evolved into a distinct entity of its own. Liberalism contains a variety of concepts and arguments about how institutions, behaviours and economic connections contain and mitigate the violent power of states. When compared to realism, it adds more factors into our field of view – especially a consideration of citizens and international organisations. Most notably, liberalism has been the traditional foil of realism in IR theory as it offers a more optimistic world view, grounded in a different reading of history to that found in realist scholarship.