Why did the flurry of summitry in the Trump years to denuclearize North Korea fall short? What is the crux of the Korean security problem? To understand peninsular security, I argue that a more holistic approach is warranted to unpack and piece together the many crosscutting and overlapping security dynamics in a cogent and coherent manner. In this article, I first argue that the Korean Peninsula should be understood as a security system writ large, comprising the United States, China, and the two Koreas as indispensable players \u00acin all major issues pertaining to peninsular security. The second section introduces complex systems theory as an analytical approach that injects more sophistication and dynamic into the otherwise overly structural analysis typical of the field. The third and fourth sections reconstruct the unfolding of major events in terms of a positive feedback loop\u2014namely, how great power realpolitik and North Korea\u2019s provocations converged and ricocheted to cause the crisis in 2017, as well as a negative feedback loop in which triangular interactions both facilitated and obstructed US\u2013North Korea wrangling. The conclusion offers some preliminary assessments of how things might play out in the future.<\/p>\n