Although most political historians presumably acknowledge the vital importance of ideas in politics, the relation between political ideas and power relations remains a remarkably neglected topic in political history. This article assesses the role of political ideas in times of deep political crisis, focusing on the Dutch neoliberals, who fiercely opposed the emerging welfare state in the aftermath of the Second World War. As the early neoliberals did not establish parties of their own, political historians have overlooked this particular political movement. Nevertheless, the early neoliberals provide a fascinating departure point for a closer examination of the political power of ideas.As this article demonstrates, neoliberals departed from social liberalism and classical liberalism in the late 1930s, and established an influential, transnational political network. After the Second World War, they managed to gain substantial publicity for their ‘battle of ideas’ against social security, without establishing parties of their own. Due to their fierce opposition to social democrats, neoliberals would play a fundamental role in the establishment of a new left-right division in Dutch politics. In doing so, they caused an internal division of the mainstream Christian democratic parties over socio-economic issues and delayed the development of the Dutch welfare state. Hoewel de meeste politiek historici het belang van ideeën in de politiek niet zullen ontkennen, is de invloed van ideeën op politieke machtsvorming nauwelijks onderzocht. Dit artikel behandelt de rol van politieke ideeën in crisistijd, en vestigt daarbij de aandacht op de Nederlandse neoliberalen. Kort na de Tweede Wereldoorlog voerden zij een felle ideeënstrijd tegen de oprukkende verzorgingsstaat. Omdat deze neoliberalen geen eigen partijen oprichtten, maar streefden naar invloed binnen gevestigde partijen, zijn zij in de politiekegeschiedschrijving tot nu toe onopgemerkt gebleven. Juist door hun afwijkende organisatievorm bieden zij echter een ...