This Policy Brief compares and contrasts the Trump administration’s 2018 Nuclear Posture Review with past reviews and its Obama predecessor. It concludes that this review offers a much harsher assessment of the security environment; it posits a more expansive role for nuclear weapons; and proposes a substantial de-emphasis on arms control. In tone and direction, the 2018 NPR signals a nuclear environment that is more menacing and more competitive, less regulated by negotiated agreement, and marked more by modernization than by reductions in forces. It focuses too much attention on Russian threats, sees weaknesses in the US deterrence posture and believes that deterrence will be bolstered by providing the president with additional usable nuclear options. While there are continuities between this NPR and earlier ones what makes this one particularly worrying is the incumbent Commander in Chief who seeks to blur past distinctions between conventional and nuclear forces.