The December signing of the long-delayed agreement by the United States, Japan, and South Korea to share information in the event of a North Korea contingency is welcome recognition of the value of trilateral cooperation in a security crisis. The limits of that agreement are proof of the powerful obstacles they face when they try to make that cooperation real.

The Pacific Forum has for more than a decade explored the benefits in and barriers to such cooperation. In 2014, we held two tabletop exercises involving senior experts and next generation specialists respectively that used North Korea-instigated WMD crises to test the three countries’ responses. The results were encouraging, demonstrating a shared sense of purpose and a readiness to surmount political obstacles to protect national interests. At the same time, however, misunderstandings were rife and the desire to work together was frustrated by the lack of a mechanism and framework to coordinate a trilateral response.

Significantly, in each simulation participants assumed that some trilateral cooperation would occur. The United Nations Command and bases would link the three countries and facilitate a coordinated response. Ironically, this minimum level of cooperation might be a hindrance of its own: ROK planners assume that they can get what they need with it and thus complain that more explicit cooperation isn’t in their national interest and is more for the US and Japan. Meanwhile, Japanese complain that their cooperation is taken for granted and that Japan is exposed to North Korean retaliation as a result.

Participants expressed the usual allied concerns regarding entrapment and abandonment: Japanese and ROK participants demanded that the US join them or back their efforts to respond to acts of aggression (even those short of war), warning in the Japanese case that a failure to do so would mean the end of the alliance. Significantly, the US met its ally’s expectations in each simulation. At the same time, each country worried that the other ally could over-react in ways that would harm its national interests. All sought to impose breaks on independent action that might escalate a conflict.

Each country is quick to assert its unique equities and vulnerabilities in a crisis that demand consideration. ROK participants insisted that their country was particularly vulnerable to the economic impact of a crisis. The Japanese asserted that they were the true targets of North Korean nuclear and missile programs, providing reasons why Pyongyang wouldn’t target other regional powers with those weapons. US participants averred that alliance concerns – questions of commitment and credibility elsewhere in the world – were underappreciated or taken for granted.

Views of North Korea differed among countries. There were divergent interpretations of North Korean signals, with Japanese and South Koreans less inclined to see a nuclear detonation (over the open ocean) as an escalation in the crisis and more of a warning about Pyongyang’s reading of the stakes. Americans interpreted a North Korea nuclear detonation as escalation, and noted that the 2014 Quadrennial Defense Review explicitly denies an adversary the option of escalating out of a crisis. This divergence also reflects differing assessments of the North Korean theory of victory; plainly, the three governments need a unified view of North Korean thinking, how it will wage a war and its aims and objectives.

The twin TTXs also provided one of the most important distinctions between senior-level and next-generation thinking. While senior experts were more focused on the need to re-establish deterrence by moving up the escalation ladder, next-generation participants believed that the risk of escalation outweighed the perceived need to reinforce deterrence.

Differences in national thinking about North Korea were also evident when participants identified preferred end states of a crisis. All agreed that reunification of the peninsula was desirable, but there was no consensus on when that was feasible. Americans were more apt to see nuclear use by Pyongyang as crossing a line that would require the dismantlement of the North’s nuclear programs. There was concern among South Korean and Japanese participants that the DPRK would see such efforts as leading inexorably to regime change and were reluctant to back the US position. To be clear, however: no participant argued that a strike against the North Korean nuclear complex could be “surgical.”

There is one final, critical takeaway from our discussions. There was disbelief, bordering on incredulity, when Japanese explained the limitations on their country’s ability to defend itself. Japanese participants made clear that they had virtually no capacity to retaliate militarily against North Korea for an attack on one of its vessels (the trigger for one of the simulations) and relied on the US to do so. As important as the absence of a military capability were the legal and constitutional restraints against cooperative responses and Koreans, senior and junior, were struck by the extent of those constraints. For their part, while better acquainted with those limits, Americans urged Japanese to think more about desired outcomes and objectives in such situations: many US participants were troubled by the inability of Japanese participants to express strategic preferences, relying heavily on the US to outline options and select objectives.

All participants bemoaned the relationship between Seoul and Tokyo that makes such disbelief possible and encourages the worst assessment of the other’s intentions. They took solace from polls that show both publics want to put a floor on their relationship and build a more functional and expansive partnership. The US has – in these exercises, but also at the Nuclear Security Summit in The Hague last year and at the Shangri-La Dialogue in Singapore last May – endeavored to bring the three countries together and provide opportunities for each leadership to demonstrate a readiness to move forward and the value of doing so, but neither Japan nor South Korea seems ready to take the first step and fatigue toward the other is growing in both countries.

While gratified by the results of our senior-level simulation, we were especially pleased that next-generation participants preferred to address future issues instead of relitigating the past. Their key findings have outlined a long list of ways to augment the bilateral relationships through trilateral means—collaboration on humanitarian assistance and disaster relief, search and rescue missions, reinforcing cyber-security, and, promoting a trilateral (rather than bilateral) General Security of Military Information Agreement, an idea that was adopted by the three governments in December. If, as many believe, a crisis on the Korean Peninsula is increasingly likely, if not inevitable, then there is a basis for being optimistic about our ability to respond. More preparation is needed, however, to overcome the operational and attitudinal impediments that loom so large.

Brad Glosserman ([email protected]) is executive director of Pacific Forum and co-author with Scott Snyder of The Japan-Korea Identity Clash (Columbia University Press, forthcoming, 2015). Julia Cunico ([email protected]) is director of the Pacific Forum Young Leaders program. This analysis draws on the PASCC-sponsored US-ROK-Japan Strategic Dialogue and the ROK-US-Japan Trilateral Young Leaders Dialogue sponsored by SKC Corporation.