Yoon’s “Kill Chain” strategy could feasibly drag the United States into a conflict with North Korea, so Washington is understandably wary. As one former US senior official put it: “To conduct a pre-emptive strike would not be an act of self-defence, and by definition this would fall under the category of an alliance decision.”
THE CONUNDRUM OF A PRE-EMPTIVE STRIKE
But it would not be the first time Washington sought to rein in Seoul. During the Cold War, various South Korean presidents made a bid to march North, and as recently as 2010 Washington had to urge restraint from South Korea’s Lee Myung-bak administration when retaliating to several North Koreans attacks.
But South Korea plainly lacks the geographic depth to absorb a North Korean first strike. The prospect of North Korea launching missiles with various ranges and altitudes at the same time makes it equally understandable that Seoul worries about overwhelming the joint US-South Korea missile defence system.
For South Korea, attacking North Korean missiles before any launch could appear logical. However, for the United States, South Korea pre-emptively attacking the North without its consent significantly raises the risks of North Korean missiles landing on its soil.
Consequently, the United States will use the EDSCG not only to increase the capability and credibility of extended deterrence but also to leverage its position as the senior ally to rein in Seoul’s temptations. This may cause discomfort in South Korea if it must seek an approval prior to attack when it already had little time to respond under “Kill Chain”.
It amounts to a conundrum. Under Moon, the alliance was put to the test when diplomacy with North Korea was flourishing. Under Yoon, the alliance is likely to be put to the test when tensions with the North are rising.
To reduce the chance of fracturing the alliance, Yoon should avoid publicly threatening to decapitate the leadership of a nuclear-armed state. The aim of diplomacy with North Korea should not be denuclearisation, but more modest, such as an arms limitation agreement, to keep relations from spiralling out of control.
Who knows whether Washington will really come to Seoul’s defence when the missiles are pointed toward the United States, too?
Khang Vu is a doctoral candidate in the Political Science Department at Boston College, where he focuses on East Asian politics and nuclear weapons. This commentary first appeared on Lowy Institute’s blog, The Interpreter.
