Redeploying U.S. Nuclear Weapons to South Korea: Background and Implications in Brief

Summary

Recent advances in North Korea’s nuclear and missile programs have led to discussions, both within South Korea and, reportedly, between the United States and South Korean officials, about the possible redeployment of U.S. nuclear weapons on the Korean Peninsula. The United States deployed nuclear weapons on the Korean Peninsula between 1958 and 1991. Although it removed the weapons as a part of a post-Cold War change in its nuclear posture, the United States remains committed to defending South Korea under the 1953 Mutual Defense Treaty and to employing nuclear weapons, if necessary, in that defense.

The only warheads remaining in the U.S. stockpile that could be deployed on the Korean Peninsula are B61 bombs. Before redeploying these to South Korea, where they would remain under U.S. control, the United States would have to recreate the infrastructure needed to house the bombs and would also have to train and certify the personnel responsible for maintaining the weapons and operating the aircraft for the nuclear mission.

Some who support the redeployment of U.S. nuclear weapons argue that their presence on the peninsula would send a powerful deterrent message to the North and demonstrate a strong commitment to the South. Their presence would allow for a more rapid nuclear response to a North Korean attack. Some also argue that weapons could serve as a “bargaining chip” with North Korea and that their presence would allow for a more rapid nuclear response to a North Korean attack. Those who oppose the redeployment argue the weapons would present a tempting target for North Korea and might prompt an attack early in a crisis. They also argue that nuclear weapons based in the United States are sufficient for deterrence, and that the costs of installing the necessary facilities on the peninsula could detract from conventional military capabilities. Finally, some assess that the cost of installing the necessary storage, security, and safety infrastructure could drain funding from other military priorities and time needed to train and certify the crews could undermine readiness for other military missions. Some analysts also assert that, if the United States believed it needed the capability to deliver nuclear weapons to North Korea in a shorter amount of time than allowed by the current force posture, it could pursue sea-based options that would not impose many of the costs or risks associated with the deployment of nuclear weapons on the peninsula.

South Korea’s President Moon Jae-in has advocated for more muscular defense options, but does not support the redeployment of U.S. tactical nuclear weapons. The Liberty Korea Party, the main opposition party, has formally called for the move. While some in South Korea believe nuclear weapons are necessary to deter the North, others, including those who maintain hope that North Korea will eliminate its program, argue that their redeployment could make it that much more difficult to pressure the North to take these steps. Further, if North Korea saw the deployment as provocative, it could further undermine stability and increase the risk of conflict on the peninsula.

China would also likely view the redeployment of U.S. nuclear weapons as provocative; it has objected to U.S. military deployments in the past. Some analysts believe that China might respond by putting more pressure on North Korea to slow its programs, while others believe that China might increase its support for North Korea in the face of a new threat and, possibly, expand its own nuclear arsenal. Japan’s reaction could also be mixed. Japan shares U.S. and South Korean concerns about the threat from North Korea, but given its historical aversion to nuclear weapons, Japan could oppose the presence of U.S. nuclear weapons near its territory. In addition, any adjustment of the U.S. military posture on the peninsula could create additional security concerns for Tokyo.