In August 1928, signatories from France, the United States and Germany signed a treaty outlawing war. This so-called Kellogg-Briand Pact was soon signed by almost every state. Yet, in the century since, countless wars have been started ... and not all of them finished. To find out whether the pact has had any impact on international relations since its inception, James speaks to Professor Oona Hathaway from Yale University. Oona and her colleague Scott Shapiro are the authors of ‘The Internationalists: How a Radical Plan to Outlaw War Remade the World’.