Editions : April-June 2018


  Japan, South Korea and the United States Nuclear Umbrella: Detterence After the Cold War
By Terence Roehrig                        
(Columbia University Press, 2017, 272 pp)

Reviewed by

Are we on the brink of nuclear conflict on the Korean Peninsula? In the wake of North Korea’s sixth nuclear test, a proliferation of medium- and long-range missile tests – most dramatically, the recent launch of Pyongyang’s Hwasong-15 ICBM capable of reaching the continental United States – and President Donald J Trump’s warning of “fire and fury,” the drumbeat of imminent war appears louder and more insistent.

It’s easy to see why public opinion in the region and headline writers around the world are concerned – regardless of the recent diplomatic lovefest between North and South leaders at the Winter Olympics. A war on the peninsula would have catastrophic consequences for everyone. Even though the United States would almost certainly prevail, the human costs, as US Secretary of Defense James Mattis has pointed out, would be huge: for Korean civilians and troops on both sides of the demilitarized zone, for the large numbers of foreign citizens who live in South Korea, and also for the tens if not hundreds of thousands of Japanese citizens who would be targeted by North Korea in a conflict that would almost certainly expand to include Japan and potentially the wider East Asia region.

So, if war is so unpalatable and clearly a last resort, why are anxiety levels increasing? Part of the concern is that an overconfident Kim Jong-un, emboldened by his recent technical successes and temperamentally eager to thumb his nose at Trump, might cross a critical “red line” that would force the United States to respond militarily. An atmospheric nuclear test by North Korea – something Pyongyang has threatened – a missile launch in the direction of Guam or conventional provocations by North Korea near the Northern Limit Line marking the maritime boundary between the two Koreas could provoke military action that might escalate rapidly to the nuclear level.

These fears are exacerbated by worries that Trump is incapable of exercising restraint. A thin-skinned, insecure and impulsive leader, devoid of empathy for either allies or adversaries, might press the nuclear button to demonstrate his resolve or simply to secure a “win” in what appears to many to have become a childish, name-calling battle of wills between two equally petulant national leaders.

Terence Roehrig, in his timely and thoughtful analysis of US nuclear deterrence in Northeast Asia, explains why such fears may be exaggerated. While the risk of conventional conflict on the Korean Peninsula should not be underestimated, we are not on the brink of nuclear Armageddon. The reasons for this are complex and multifaceted.

First and foremost, the United States remains committed to providing extended deterrence to its key allies in the region: Japan and South Korea. In a detailed analysis of both the historical development and current assumptions underpinning US nuclear doctrine, Roehrig shows how successive US administrations have sought to reinforce the key ingredients of credibility and resolve that are at the heart of an effective deterrence strategy.

This is partly a matter of declaratory policy, expressed most recently in President Barack Obama’s 2010 Nuclear Posture Review. By intentionally not committing to a no first use nuclear policy and deliberately remaining ambiguous about the precise circumstances in which it might use nuclear weapons, the United States can deter an adversary such as North Korea from attacking US allies, whether with conventional or unconventional weapons (nuclear, biological or chemical). Bolstering this rhetoric with concrete demonstrations of US military capabilities, such as sending nuclear-capable US B-52 and B-1 stealth bombers to fly close to or through North Korean airspace, as the Trump administration has done recently, sends a clear signal of intent to North Korea.

The credibility of such signals is strengthened also by the diversity of strategic options available to America. Extended deterrence relies on multiple military means, both conventional and nuclear, all of which have the potential to destroy North Korea. The overwhelming and destructive capacity of US conventional forces to eliminate North Korea’s political and military leadership is sufficient, in Roehrig’s judgment, to deter a rational Kim Jong-un from attacking South Korea.

What happens, however, once North Korea acquires the ability to target the United States with nuclear weapons, as seems increasingly likely within the next year or so? If there were a credible risk that Pyongyang could destroy Washington, San Francisco or New York, would an American president be prepared to go to war with North Korea in order to protect its regional allies? For policy makers in Seoul or Tokyo, this uncertainty about US intentions has strengthened calls at home for South Korea and Japan to acquire their own nuclear capability to deter an attack from North Korea. If this were to happen, the long-term goal of the United States to avoid nuclear proliferation would be undercut and the risk of nuclear conflict would increase substantially.

In response to allied fears of US abandonment and this “decoupling” scenario, recent US administrations have worked to reinforce their commitment to Japan and South Korea, not just via formal declarations on the reliability of extended deterrence, but by establishing since 2010 new bilateral deterrence dialogue mechanisms with military and political partners in Seoul and Tokyo, and by working closely to enhance interoperability and the military capacities of America’s allies – developments that Roehrig describes in detail.

This is important, given both the past and present willingness of Japanese and South Korean political elites to consider developing their own nuclear capabilities. Roehrig documents the fascinating and rarely explored history of such thinking, revealing in the process the gap between public views – frequently ambivalent or opposed to acquiring nuclear weapons, particularly in Japan – and those of government officials and politicians, often more receptive to going nuclear, either for strategic reasons or to boost national status.

Where allies and adversaries are involved, effective extended deterrence involves important asymmetries. It takes relatively little resolve to deter an adversary from acting provocatively, and a lot more to reassure an ally that it won’t be abandoned. In such situations, coherent signaling and consistent messaging are important.

It makes sense to warn Pyongyang that it faces certain destruction if it attacks South Korea, Japan or US forces in the region. However, suggesting, as US Senator Lindsey Graham has done recently, that war is increasingly probable if North Korea does not give up its nuclear assets may alarm US allies worried that Washington will act militarily without their approval. On this critically important issue, Roehrig’s analysis is noncommittal, presumably because there are limits to what we can learn from the public record about the sort of guarantees that may or may not have been offered by the United States to its allies.

One hopes that behind the scenes, the Trump administration has provided enough reassurance to South Korean and Japanese officials that military action is not only a last resort but also one that will involve their consent. Successful alliances depend on cooperation and common interests. A US president who appears determined always to put “America first” may not be the most reliable guarantor of such cooperation. Ambiguity in this context may be anything but strategic, and in fact may increase rather than diminish the risk of conflict.


John Nilsson-Wright is a senior lecturer at the University of Cambridge and a regional editor for Global Asia, a journal of the East Asia Foundation, with which Strategic Review has a content-sharing agreement.

Please login to leave a comment

Related Articles

The News, But Shorter, Delivered straight to your inbox

By signing up, you agree to our Privacy Policy. And agree to data transfer policy.