This article deals with one of the most basic issues pertaining to peace and conflict studies, namely, the need to secure stability and trust within and between nations. This is not least a challenge in Europe after a century which saw two world wars springing from unrest on the European continent. The article takes as its point of departure the claim that the challenges facing the European Union will require extensive and mutual trust to ensure compliance. Some have argued that a shared European-wide national identity is necessary to ensure such stability of practices and institutions. The philosopher David Miller is pessimistic about the prospects of European-wide nationalism of the appropriate sort. The present article provides an in-depth and critical discussion of Miller's argument, and concludes that Miller's defence of nationalism as the unique source of trust is unconvincing. Moreover, Miller's pessimism regarding the European Union is premature, if relevant at all. Alternative grounds for supporting common institutions are available, and may be within reach for the European Union. The shared bases among citizens need not include a broad range of values and cultural belonging, but might plausibly be restricted to Just Patriotism of the kind suggested in the Liberal Contractualist tradition.