The Democratic People's Republic of Korea is well on its way to establishing nuclear forces that can strike targets throughout the Republic of Korea (ROK) and Japan, and beyond. It has deployed medium-range ballistic missiles. It tested nuclear weapons in 2006 and 2009. It is likely to be developing nuclear warheads deliverable by ballistic missiles. While international efforts might get North Korea to eliminate its nuclear weapons program, this seems most unlikely. Thus, the ROK-U.S. alliance must respond to this evolving threat.
The alliance has been strengthening its extended deterrence arrangements. In the many high-level meetings of alliance leaders since the first North Korean nuclear test, a variety of steps have been taken. In June of 2009, the presidents of the two allies signed the Joint Vision for the ROK-U.S. Alliance, pledging to build a comprehensive strategic alliance of bilateral, regional, and global scope. More specific changes are apparent if we compare the statements made at the end of the yearly Alliance Security Consultative Meetings (SCMs) in 2006, held just after North Korea's first nuclear test, and those held in 2011 and 2012.
In the 2006 SCM, "Secretary of Defense [Donald] Rumsfeld offered assurances of firm U.S. commitment and immediate support to the ROK, including continuation of the extended deterrence offered by the U.S. nuclear umbrella, consistent with the Mutual Defense Treaty." (1) In the 2011 SCM:
Secretary of Defense [Leon] Panetta reaffirmed the continued U.S. commitment to provide and strengthen extended deterrence for the ROK, using the full range of capabilities, including the U.S. nuclear umbrella, conventional strike, and missile defense capabilities. Moreover, the Minister and the Secretary decided to further develop the Extended Deterrence Policy Committee (EDPC), already held twice this year, which serves as a cooperation mechanism to enhance the effectiveness of extended deterrence. To this end, the Minister and the Secretary endorsed the "EDPC Multi-year Work Plan," and decided to develop a tailored bilateral deterrence strategy including future activities, such as the ROK-U.S. Extended Deterrence Table Top Exercise (TTX), to enhance effective deterrence options against the nuclear and WMD threats from North Korea. (2)
Then in the 2012 SCM:
the Secretary and the Minister decided to develop a tailored bilateral deterrence strategy through the Extended Deterrence Policy Committee ... particularly against North Korean nuclear and WMD threats. To this end, the Secretary and the Minister approved the joint concepts and principles of tailored deterrence, upon which the bilateral deterrence strategy is to be based. (3)
The increasing breadth of the U.S. extended deterrence commitments reflects the ROK's need for assurance that it can continue to rely on these commitments. It demonstrates U.S. willingness to provide such assurance. Moreover, it highlights the need to take further concrete and timely steps to strengthen extended deterrence as the North Korean nuclear threat evolves. But what steps should be taken and under what circumstances?
This article summarizes the more important arguments for why and how the extended deterrence arrangements for the alliance might be strengthened. It considers both the technical steps already identified in SCM communiques and further steps that might be needed. The purpose is to illustrate how the more important interests of the two allies might be expected to shape further strengthening of the alliance's extended nuclear deterrence. The article then describes how a small nuclear force might enable North Korea to challenge the alliance with intense crises or perhaps even by initiating the use of nuclear weapons. Next, the article argues that there is already a strong basis for confidence in the alliance's extended nuclear deterrence arrangements, but nonetheless that further strengthening would be needed as North Korean nuclear capabilities evolve. …