The introduction outlines the period known as the Second Cold War, circa 1979–85. It marked the end of the détente, and escalated into the most dangerous phase of the conflict since the Cuban Missile Crisis. As fears of nuclear war were raised, so the domestic schisms deepened. The largest peacetime military buildup was challenged by the largest peacetime peace movement. I discuss the reasons for the rise in US–Soviet tensions and explain how they were eased – even before the arrival of Mikhail Gorbachev in 1985. The preface highlights the role of domestic politics in shaping American foreign policy during the administrations of Jimmy Carter and Ronald Reagan. Both presidents changed course – Carter becoming more hawkish; Reagan more open to negotiation – by the end of their first terms, pushed by international affairs yet simultaneously incentivized by potential domestic gains to be found within their transformation. These dramatic “reversals” helped lead to the rise and fall of the last great Cold War struggle. I argue that the convergence of the international and domestic agendas (the “intermestic”) is the key to understanding US decision-making.