With its 2018 Nuclear Posture Review, the Trump administration expanded the scope of US nuclear deterrence, re-emphasizing the importance of non-strategic nuclear weapons, perceptively lowering the threshold for nuclear use and casting doubt on the future of arms control. The authors argue that these changes are consistent with the administration's wider ‘peace through strength’ approach that draws on traditional Republican thinking on security policy. While designed to demonstrate credibility and resolve to both allies and adversaries, however, this assertive approach to security policy and specifically nuclear policy as a necessary precursor to renewed engagement in strategic negotiations may have unintended consequences. This article focuses on European reactions to the strategy and argues that the Trump administration's nuclear posture challenges common European understandings in three principal areas. First, changes to US declaratory policy contest European assumptions on the role of nuclear weapons in defending NATO. Second, US modernization plans and their implications for intra-alliance relations risk accentuating controversial debates about the US commitment to Europe. Third, the apparent US rejection of arms control widens the scope for discord with European leaders. If European leaders assert a clear and credible alternative vision advocating nuclear restraint, risk reduction and arms control they could rebuild trust and confidence between the United States, NATO and Russia, demonstrating real strength and ultimately leading to more genuine opportunities for peace and sustainable European security.