Preventing Decoupling between the United States and South Korea

North Korea’s leader Kim Jong Un (L) shakes hands with US President Donald Trump last summer. Photo Credit: Getty Images

By: Evan Cooper, Columnist

One of the hazards of President Donald Trump’s “pure bilateralism” approach to foreign policy is that the policies of allies can become unaligned from those being pursued by the United States.[i] Misalignments can turn relationships that would otherwise increase negotiating strength into problems of their own, separate from the issues trying to be solved through the bilateral negotiations. This problem is playing out in the ongoing deliberations between the U.S., South Korea, and North Korea. As the Trump administration maintains its position on North Korean denuclearization, the risk of decoupling between the U.S. and South Korea has intensified, which furthers the security threat emanating from the Korean Peninsula rather than mitigating it.

At first glance, it may appear that the US and South Korea are pursuing similar policies towards the North. Despite heightened tensions during the “fire and fury” period of the Trump administration, the U.S. has taken a less provocative approach since the June 2018 meeting between Trump and North Korean leader Kim Jong-un in Singapore, with a reported second meeting to take place some time in early 2019.[ii] Trump has said the he and Kim “fell in love” through their exchange of letters, and South Korean President Moon Jae-in recently said he communicated to Kim that Trump intends to “fulfill Chairman Kim’s wishes.”[iii] Moon has similarly sought a friendly relationship with the North Korean dictator. They were pictured warmly embracing one another during their September meeting in Pyongyang, the third meeting between the two, where they signed a broad agreement pledging to pursue denuclearization of the peninsula and reduce tensions.[iv]

But despite the warm sentiments shared among the three leaders, the September meeting revealed the fundamental divergence between U.S. and South Korean policy being exploited by North Korea. It arises from the semantic issue of “denuclearization” and the different visions of how the disputed endpoint will be achieved. As recently reiterated by Kim, denuclearization necessarily means a removal of the nuclear threat from the Korean peninsula, meaning a removal of American troops and a retraction of the American nuclear umbrella that protects South Korea.[v] But the U.S. has indicated it intends to pressure the North through continued UN sanctions and bilateral talks until they disarm.[vi]

South Korea is taking a very different approach from the US. President Moon has sought to induce denuclearization by pursuing a diplomatic agenda that has included removing land mines from the Demilitarized Zone (DMZ), setting up military commissions to prevent miscommunication between the two large forces, offering to submit a joint application to host the summer Olympics, and posing economic deals that all aim to bring the two countries closer together.[vii] Moon has all but given up on trying to get the North to dismantle its nuclear program, stating vaguely that he is pursuing denuclearization while focusing on reducing tensions. Moon has made clear that the South will pursue his diplomatic agenda even if it run contrary to the economic starvation approach taken by the U.S. and potentially violates UN sanctions, the very sanctions regime that the U.S. is counting on keeping pressure on the North to force denuclearization.[viii]

South Korea’s approach has moved denuclearization to the back burner, which has not gone unremarked on by the US. The US Ambassador to South Korea, Harry Harris, delicately expressed concern in a statement that read in part, “We are, of course, cognizant of the priority that President Moon Jae-in and his administration have placed on improving South-North relations. I believe this inter-Korean dialogue must remain linked to denuclearization, and South Korea synchronized with the United States.”[ix] Trump has also commented on the South’s diplomatic overtures, accusing South Korea of appeasement towards the north.[x]

It is possible that the U.S. will back down from the demand for unilateral denuclearization it has maintained thus far, but if it continues its current approach and South Korea maintains its focus on cooperative diplomacy, full decoupling could occur. Such a scenario is not difficult to imagine. Trump may see Moon’s diplomacy as undercutting his approach and return to his criticism and threats towards the South.[xi] The U.S., continuing its bilateral method, may make an agreement with the North, as Trump as indicated he would like, to be able to say they have fully removed the nuclear threat, by striking a deal that includes the removal of American troops from the peninsula and the removal of the nuclear deterrent threat if the South is attacked.[xii] According to former Trump advisor Steve Bannon, such a deal had been discussed in the White House.[xiii]

The result of such a deal would immensely empower to North Korea, even if it accomplishes the immediate US goal of reducing any direct nuclear threat. With US forces off the peninsula and an administration hostile towards the South, North Korea would have far more leverage in any future diplomacy with the South. If the diplomatic overtures from the South were to fail and slip towards hostilities, North Korea would not face the nuclear and conventional deterrence of a US presence on the DMZ. The U.S. might reduce the North Korean threat in the short term, but it would lose the far more valuable South Korean alliance and increase the risk of conflict on the peninsula.

Such a future is far from guaranteed and it can be purposely avoided. The Trump administration can keep its hard line on sanctions relief while allowing South Korean overtures. Successful agreements between the North and the South may undercut sanctions somewhat, but by no means would they remove the immense economic pressure North Korea is under. Most importantly, the U.S. and South Korea must find a common definition of denuclearization and communicate how they each seek to pursue it. They need not use the same methods, but coordination is needed to prevent the perception that they are impeding one another. If a fundamental difference in their approaches does arise, so does the potential for an outcome neither the U.S. nor South Korea wants: a North Korea that has far more leverage against both countries. 


[i] Danielle Allen, “Trump’s foreign policy is perfectly coherent,” The Washington Post, July 23, 2018,

[ii] Hallie Jackson and Saphora Smith, “Trump says he will likely meet with North Korea’s Kim in early 2019,” NBC News, December 2, 2018,

[iii] “Trump ‘likes’ North Korean leader and will ‘fulfil Chairman Kim’s wishes’,” The Guardian, December 2, 2018,

[iv] Benjamin Haas, “Kim Jong-un greets Moon Jae-in as inter-Korean summit starts,” The Guardian, September 18, 2018,

[v] Min Joo Kim, “North Korea rejects denuclearization unless U.S. ‘nuclear threat’ is eliminated,” The Washington Post, December 20, 2018,; Anna Fifield, “North Korea’s definition of ‘denuclearization’ is very different from Trump’s,” The Washington Post, April 9, 2018,

[vi] Matthew Pennington, “Pompeo backs away from denuclearization goal for North Korea,” Military Times, October 3, 2018,

[vii] Joori Roh and Josh Smith, “North, South Korea begin removing landmines along fortified border,” Reuters, September 30, 2018,; Abby Bard, “America Must Support South Korea’s Diplomacy,” The National Interest, September 11, 2018,

[viii] Elizabeth Shim, “Seoul: No sanctions exemption for inter-Korea liaison office,” United Press International, August 30, 2018,

[ix] Cho Yi-jun and Kim Jin-myung, “U.S. Warns Seoul Over N.Korea Sanctions,” The Chosun Ilbo, October 18, 2018,

[x] Donald Trump, Twitter post, September 3, 2017, 4:46 AM,

[xi] Glen Thrust and Mark Landler, “Why Trump, After North Korea’s Test, Aimed His Sharpest Fire at the South,” New York Times, September 3, 2017,

[xii] Edward Wong and David Sanger, “Trump to Meet With Kim Jong-un, Despite North Korea’s Lapses, Bolton Says,” New York Times, December 4, 2018,

[xiii] Thomas Wright, “The Biggest Danger of North Korea Talks,” The Atlantic, March 9, 2018,

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