Why Did the United States Choose Assurance or Coercion to Terminate the ROK's Nuclear Pursuit?

Existing scholarship has been focused on how a patron restrains a client's nuclear aspiration. Some scholars argue that assurance pacifies the client and restrains its nuclear weapons development, but others insist that coercion forces the client to inhibit its nuclear behavior. However, these studies rarely explain why a patron chooses to employ assurance or coercion toward the nuclear-aspiring client. By refining the conventional understanding of security assurance and entrapment risk, the paper argues that a patron provides assurance to take entrapment risk and prevent destabilizing regional order due to nuclear proliferation. The paper examines the U.S. alliance management over the ROK's nuclear activities. From 1974 to 1979, the United States perceived a growing entrapment risk and premature nuclear proliferation risk. As Washington's policy options were limited by ongoing U.S. disengagement throughout the 1970s, the United States sought to inhibit the ROK's nuclear pursuit by coercion. However, the United States failed to completely reverse its nuclear activities as the ROK responded with a nuclear hedging strategy. From 1979 to 1982, the United States perceived a diminishing entrapment risk and enduring nuclear proliferation risk. The United States provided a stronger security guarantee to assure the ROK, which, in turn, terminated the remaining nuclear weapons-related programs. The paper finds that the United States considers different risks at the system level and at the alliance level in carrying out its security policies toward the ROK.