The Pacific Forum, with the Asan Institute for Policy Studies and with support from the Project on Advanced Systems and Concepts for Countering WMD (PASCC) and the Defense Threat Reduction Agency (DTRA), held a US-ROK-Japan Extended Deterrence Trilateral Dialogue on July 19-21, 2015. Forty-one US, ROK, and Japanese experts, officials, military officers, and observers, along with 19 Pacific Forum Young Leaders, attended in their private capacities. Key findings include:

The primary challenges that the United States faces from its chief competitors in Northeast Asia – China and North Korea – are similar. Each is trying to use speed, geography, and asymmetry of stakes to reach their objectives, while avoiding a US military response.

All participants support increased trilateral cooperation but understand that political dynamics between Seoul and Tokyo will limit progress. One ROK participant insisted that political support for trilateralism in South Korea is only possible if the three countries focus on countering a North Korean threat. “China is the ceiling to how far trilateral cooperation can go,” an argument consistent with previous meetings. A US participant argued that trilateral cooperation and coordination is not sufficient. He called for greater interoperability that leads to deep integration of security policies.

South Korea and Japan remain concerned with gray zone challenges from North Korea and China respectively and want more clarity about how the United States will contribute to their defense in these situations. Some US participants noted that the US can only do so much to help allies to counter provocations. Others encouraged more seamless integration of planning and greater US support for allied efforts to protect their interests if challenged. Some US participants, however, stressed that allies are primarily responsible for their own defense against gray zone challenges.

ROK participants remain concerned about Japan’s move toward collective self-defense (CSD). They recognize that Japan could play an important role in the Asia-Pacific, but want assurances that Japan will not be involved in a Korean Peninsula contingency without prior approval from Seoul.

Japanese participants heard the ROK message and provided assurances that no action would occur in a Korean contingency without Seoul’s consent. They supported CSD and the new US-Japan defense guidelines, while emphasizing the limitations of each.

With its new security legislation, Japan faces assurance problems similar to those the US has addressed with its allies: Regional countries, especially South Korea, want more detail about the circumstances in which CSD will be exercised. Japanese participants countered that ambiguity is inevitable as not all contingencies can be anticipated.

An ROK participant proposed a trilateral strategic deterrence committee to coordinate nuclear plans and policies in an effort to show joint nuclear resolve.

The conference featured a tabletop exercise in which teams representing the US, Japan, and South Korea responded to a crisis. In the first move, North Korea invaded and overran Daechong Island, taking hostages and seizing control of the island. In move two, the DPRK responded to ROK threats of retaliation by insisting that it plans to keep Daechong, demanding that Seoul abandon a neighboring island, Baengnyeongdo, renewing its commitment to redraw the Northern Limit Line, dispersing road mobile missiles, and issuing thinly-veiled weapons of mass destruction (WMD) threats against the ROK and Japan. In an interjection during deliberations, it was revealed that North Korea detonated a nuclear device over the Sea of Japan.

Areas of convergence

• Participants from all three countries were unsure of North Korean goals and objectives in the scenario, but thought that they were likely limited, perhaps to achieve territorial gain or to demonstrate strength to a domestic audience.

• US and South Korean participants were determined to respond to North Korea’s aggression decisively, including rolling back territorial gains, recovering hostages, and punishing Pyongyang for its provocation. Participants from each country did, however, recognize the potential for escalation after the US/ROK response.

• South Korean participants proposed a unilateral ROK military response to retake the island, strike North Korean military bases that had supported the initial invasion, and additional escalatory steps. They expressed a strong sense that, after five years of North Korean provocations, Seoul is itching to strike back at North Korea decisively (and disproportionately).

• Initially worried that the United States might try to restrain their military action, South Korea participants were surprised at the extent of US support for decisive military action.

• Japanese participants supported the parameters of the US and ROK response and offered support. They also expressed concern with overreaction and escalation, particularly if it might spillover and affect Japan, and hoped to be consulted as response options were developed and pursued.

• After the second move, all three teams supported a decisive military response to include retaking the lost island and conventional strikes in North Korea. The ROK team thought the situation was quickly moving from a limited provocation toward a full-scale war and it needed to prepare for inevitable escalation. They also proposed that eliminating the North Korean nuclear threat be the top priority.

Areas of disagreement

• While generally supportive of South Korea’s actions, US participants expected that Seoul would pursue greater consultation and coordination with Washington and Combined Forces Command if such a crisis arose. Many argued that North Korean invasion of an island would be an act of war that should initiate the transfer of operational control to the United States.

• Areas of potential disagreement between Japan and the ROK arose during the first move. First, the Japan team was more concerned with escalation than the ROK team. Second, the Japanese proposed preparing for non-combatant evacuation operations, while the ROK side cautioned against such a step, arguing that it would induce panic. Third, the Japan team proposed taking the issue to the UNSC, while the South Korean team supported an initial unilateral response.

• In move two, Japan cautioned that it would support a tactical response but not full-scale war, all-out invasion, or regime change. The team again expressed a desire to be consulted before the US and ROK decided on a response. The US team also hoped that the ROK would not, at this point, establish regime change as its military objective, which caused some consternation among Korean participants.

Nuclear signaling

• ROK participants expected that, in this type of scenario, North Korea would be likely to issue nuclear threats early in the crisis. They requested that the United States show nuclear resolve. While they did not express a clear preference for a mechanism of doing so, the deployment of nuclear-capable assets to Guam was seen as a desirable initial step.

• The ROK team said that North Korea’s detonation of a nuclear weapon changed their discussions. This showed them that North Korea was willing to escalate all the way. The US team also saw use of nuclear weapons as a game changer and argued that it changed the US interests at stake.

• Japan, however, saw the nuclear detonation as an attempt at coercion, not an indication that North Korea was preparing to use additional nuclear weapons. They noted that North Korea’s overriding interest in regime survival would prevent it from using nuclear weapons against a population center.

• Use of a nuclear device did not surprise US, ROK, and Japanese participants, all of whom seemed to have accepted that nuclear use was a real possibility, although most (but not all) thought it would initially be limited to a warning shot or signaling as opposed to an attack on troops or population centers.

• A Korean participant argued that if North Korea was able to hold on to the island by using nuclear coercion, then Seoul would likely leave the NPT and acquire nuclear weapons.

De-escalation

• It is essential that the three countries agree on what constitutes North Korean de-escalation (or what would constitute “offramps” for the crisis). Participants reached no consensus on what Pyongyang could/should do to defuse the crisis that would satisfy their need to punish North Korea for its aggression.

• When the US and ROK speak of escalation they use different contexts: Americans speak of escalation in the context of nuclear use, Koreans are talking about escalation of aims – i.e., unification.

China’s role

• Participants from the US, South Korea, and Japan all acknowledged that China would play a critical role in this type of crisis. For some, China would be unlikely to offer support and may even side with North Korea; others saw an opportunity to distance Beijing from Pyongyang.

• ROK thinking about China was inconsistent. On one hand, ROK participants argued for taking Chinese sensitivities into account when considering action in Northeast Asia to maintain leverage with Beijing to deal with Pyongyang. Yet, in the scenario, the ROK side wanted to act before the UNSC could take up the issue for fear that China would block consideration – which suggests China won’t support the ROK.

Other points

• The ROK team noted that the ROK would need time for full-scale mobilization and proposed an operational pause. US participants were skeptical that North Korea would allow this to occur unchallenged.

• A Japanese participant highlighted the absence of established channels through which the SDF could communicate with Korea in a crisis. Any communications would be ad hoc and indirect.

• The exercise highlighted the difficulty of effectively managing a North Korean initiated crisis. Several participants wondered whether it would be possible for the US, ROK, and Japan to achieve their goals and objectives without accepting a significant risk of nuclear escalation.