Major political developments at the end of 2024 have ushered in new unpredictability in the US-South Korea relationship for 2025. First came the re-election of Donald Trump in the United States, followed by dramatic events in South Korea that are still evolving after President Yoon Suk Yeol’s short-lived declaration of martial law. Deep political division is a powerful undercurrent contributing to both these developments, the aftermath of which will play out in unique and uncertain ways in each country over the course of 2025.