Mineral nitrogen (N) application in agriculture has significantly increased food production over the past century. However, the intensive use of N fertilizers also impacts negatively the environment, notably through greenhouse gas emissions and biodiversity loss and remains a major challenge for policymakers. In this paper, we explore the effects of a public policy aiming at halving agricultural mineral nitrogen use across the European Union (EU). We investigate the impacts on food security, climate mitigation, and biodiversity conservation and we analyze the potential trade-offs and synergies between them. Despite the uncertainties associated with monetary valuation and the choice of modeling approach, our results show that climate- and biodiversity-related benefits of halving N use in EU agriculture more than offset the decrease in agricultural benefits.