This article examines interwar peace activism by focusing on the personal emotional process that provokes disillusionment. This study documents how peace aspirations collapsed for two activists during the Washington Naval Disarmament Conference and again at the start of the Second World War. The former destroyed their faith that peace could be obtained through international mediation while the latter prompted a rejection of all interwar peace organizations. This article argues that while war memory often prompted involvement in interwar peace movements, trauma decreased psychological resilience—effectively leaving individuals prone to disillusionment when faced with the political machinery of conflict negotiation.