The national security overflow trap: Analyzing the causes of "security overflow" in the U.S.-China strategic competition

The U.S.-China relationship has undergone a profound transformation since the onset of the trade war in 2018. Once defined by mutual economic interdependence, bilateral cooperation has increasingly been supplanted by a pervasive logic of “national security.” This paper investigates the phenomenon of “security over-expansion” — the strategic inflation of national security discourse into economic and technological realms — as a central dynamic in contemporary U.S.-China strategic competition. Through a dual-theoretical lens of securitization theory and institutionalization theory, the paper analyzes how both nations reframe non-security issues such as technology, investment, and supply chains into matters of national security. The study reveals that this securitization trend structurally erodes international trust, fragments global governance regimes, and fosters a new form of institutionalized confrontation. It concludes with a call to re-establish normative boundaries for security claims to safeguard global institutional integrity.