The US–Republic of Korea (ROK or South Korea) alliance underwent severe strains during the Trump era. However, we can only understand such strains by situating them in a larger post-Cold War context, wherein successive US and ROK administrations have sought to transform and upgrade the alliance. The Trump administration’s unorthodox policy approach accelerated alliance tensions and thus revealed the psychological and institutional limits and contradictions inherent to this larger transformation, even if Trump did not create the underlying dynamics driving them. This chapter explores these tensions through a survey of several issue areas under Trump in relation to which the allies held contrasting if not clashing positions, including perceptions of the North Korean threat and engagement with Pyongyang; the transfer of wartime operational control (OPCON) of the ROK military from the US back to South Korea; alliance cost-sharing; and the alliance’s place within the wider region. While alliance relations have returned to a degree of normalcy under President Biden, these same issues that caused alliance discord under Trump are no less salient today.

In 1990, the United States passed groundbreaking amendments to the Clean Air Act to combat acid rain. This legislation has saved countless lives, spurred innovation, and helped lay the groundwork for more ambitious climate policy. But as one might suspect, it was a major legislative battle. And one part largely ignored in the literature on this momentous legislative achievement was a proposal from the infamous Senator Robert Byrd of West Virginia. He and a group of lawmakers fought for substantial funding for coal workers that would be put out of work by the acid rain law. We tell the story of this legislative battle, which highlights themes discussed in the book. We then contrast the Appalachian coal transition with Germany's coal phase-out, including how their political and social systems facilitate or frustrate transitions.