This is a major study of French foreign and security policy before, during and after the First World War. Peter Jackson examines the interplay between two contending conceptions of security: the first based on traditional practices of power politics and the second on internationalist doctrines that emerged in the late nineteenth century. He pays particular attention to the social and political context in which security policy was made and to the cultural dynamics of the policy-making process. The result is a comprehensive reassessment of France’s security policy in the era of the Great War. The book reconsiders the evolution of French war aims and reinterprets the peace policy of the Clemenceau government in 1919. It provides a perspective on the foreign policy of successive French governments in the early 1920s, and also shows that internationalist ideas were far more influential over this entire period than is commonly understood.