Liberal Norms or Coercive Counterproliferation: The American Response to Potential South Korean Nuclearization

Do liberal norms impact nonproliferation when both proliferator and counterproliferator are liberal states? This question is underexplored in the nonproliferation literature which mostly conceptualizes counterproliferation through a realist lens. But the liberal community of states rejects the use of power‐political methods like threats and sanctions among its members as illegitimate. Thus, counterproliferation coercion creates unique problems among liberal states: It is a normative violation of the counterproliferator's liberal identity and its claim to lead the liberal community. It also generates audience costs, like hedging, by the coerced partner and other liberal states who witness the coercion. These pressures create a principles‐vs‐interests trade‐off: if a liberal counterproliferator coerces a liberal proliferator on behalf of its nonproliferation interests, it simultaneously contravenes its liberal principles. This paper integrates these insights into a ‘liberal proliferation model’ and applies it to contemporary South Korea‐US tension over South Korea's nuclear aspirations. The empirical analysis finds that the model fits well, drawing genuine distinctions with realist‐inflected, powerand‐ threats nonproliferation theory ‐ including a looming principles‐orinterests choice for America, because its efforts to dissuade South Korea from nuclearization have only partly succeeded. America has accommodated liberal nuclearizers (Israel and India) before, so it is unclear how it will respond.