Abstract: This paper examines the interactions between the USA and the expanding ecosystem of East Asian and Asia-Pacific institutions. Concentrating on the period since the Global Financial Crisis of 2008–2009, it analyzes the ‘rival regionalisms’ that are now mushrooming throughout the region. Critical is the competition between nominally cooperative institutions and continued state-to-state suspicions that handicap efforts to forge regional institutions able to redress the region’s most contentious issues. Nonetheless, national mistrust of regional bodies is less evident in areas such as trade and finance where many actors envision the possibility of win-win solutions even as they remain more difficult to envision in issues touching on hard security The paper concludes by exploring what looks to be a new American disengagement from Asia-Pacific regional institutions as a consequence of the presidency of Donald Trump. Full text available here.