Trumpism—the political ideology and praxis of the 2017–2021 U.S. administration—catalyzed the post-1945 Liberal World Order problem, according to this analysis. Based on the scholarly consensus that the LWO faced pre-existing stresses from geopolitical shifts, economic discontent, and institutional fatigue, the analysis uses a qualitative secondary methodology to determine if this confrontation caused systemic decline, adaptation, or transformation. The research synthesises International Relations literature, policy papers, and historical analysis to identify disruptive factors in institutional, geopolitical, and domestic-political domains. Trumpism accelerated a contentious international system shift, not its end. In contrast to a story of simple collapse, fundamental institutions like NATO and the WTO have survived but are now governed by conditionality and geopolitical negotiation. The investigation also finds a major ideational shift: the legitimisation of illiberal, transactional sovereignty as a challenger to liberal principles. Thus, the emerging order has a hybrid structure—a “multiplex” of interrelated fragmentation. This structure has competing technospheres, durable economic interconnectedness, and exclusive, interest-based minilateral clubs instead of inclusive multilateralism. A key finding is that democratic states, particularly the US, are most affected by domestic political volatility, which drives systemic uncertainty. A feedback loop between local polarisation and international legitimacy underpins the geopolitical shift. While the Universalist, hegemonic LWO is irrevocably changing, it is becoming more contested, less liberal, and geopolitically segmented. The study concludes that democratic states must strengthen domestic democratic resilience, pursue “principled minilateralism,” and adopt clear-eyed coexistence strategies to navigate an era defined not by the restoration of a defunct order but by the managed steering of an ongoing and uncertain transformation.