As the Dust Settles, How Healthy is the ROK-US Alliance?

President Joe Biden participates in a press conference with South Korean President Moon Jae-in Friday, May 21, 2021, in the East Room of the White House. (Official White House Photo by Cameron Smith)

A summit meeting took place on May 21 between President Moon Jae-in of South Korea and US President Joseph Biden. At many previous US-Republic of Korea (ROK) summits, the threat posed by North Korea has been the most important issue discussed, but the remarkable summit joint statement underscores how much this one was clearly focused on China. The alliance between the ROK and the US has historically been predominantly military in character and focused on threats to peace on the Korean Peninsula. But it is now being integrated into the broader US Indo-Pacific Strategy, with its focus on the threat from China, as well as cooperation on more general regional and global issues.

South Korea and the US-led Indo-Pacific Strategy

Moon went into the summit hoping that the new US president would offer some kind of support for his Korean Peninsula peace initiative, which has been an important part of his domestic political platform. Biden’s priority is China, however, and he worries that South Korea is too reliant upon China to remain a staunch US ally. Biden’s policy for now on North Korea is to avoid the mistakes of previous US presidents. While Moon and Biden are in very different places, they somehow managed to reconcile their positions. In fact, Moon has made a significant shift. Previous ROK administrations have deployed troops for missions beyond the peninsula to support US policy aims, but now Moon, by accommodating Biden’s new vision for the US Indo-Pacific Strategy, has tacitly involved South Korea in the US-led attempt to contain China. Although China was not directly mentioned in the joint statement, there were references to the South China Sea (SCS) and Taiwan.

For the past four years, Moon has carefully avoided any suggestion of standing with the US against China. He has played down the importance of trilateral security cooperation between the US, Japan and South Korea and steadfastly declined to join the Quadrilateral Security Dialogue (QUAD) comprising the US, Japan, India and Australia. But now South Korea is apparently ready to lend rhetorical support to US views on sensitive regional issues, such as Taiwan and the SCS; however, the prospect of South Korea actually becoming involved in directly opposing China in either situation is remote, at least while the North Korean military threat continues. Therefore, South Korea’s diplomatic contribution to this new vision of the US Indo-Pacific Strategy will likely be limited to hortatory support for a rules-based regional security order for the foreseeable future.

In addition to these more traditional security relations, the joint statement also discussed human rights in Myanmar, supply-chain cooperation for semiconductors and COVID-19 vaccines, enhanced cooperation in space and cybersecurity, and South Korean investment in innovative technologies such as artificial intelligence, 5G and 6G, and electric vehicle batteries. In effect, as part of the greater alignment with the US-led Indo-Pacific Strategy, the ROK-US alliance has been expanded beyond the military sphere: it now encompasses the most serious global threats to human and economic security.

Examining the State of the ROK-US Alliance

The summit joint statement gives the impression that the military alliance between South Korea and the United States is in great condition and getting stronger. There are several reasons, however, to doubt whether things are really as healthy as Biden and Moon would have us believe.

First, since Moon took office, he has significantly weakened the combined defense posture with the United States. In the name of exercising military sovereignty, he has sought to expedite the taking back of operational control authority in wartime (OPCON transfer) from US Forces Korea (USFK) to the ROK Armed Forces. This is being implemented in three phases: Initial operational capability was verified in 2019, Moon hoped for full operational capability this year, and full mission capability achieved next year. The ROK military’s Defense Reform 2.0 initiative was intended to make the ROK military more independent and autonomous, so as to meet the conditions-based OPCON transfer agreed in 2014. At that time, three conditions were set for a smooth and effective transfer: The ROK should acquire some key military capabilities necessary to lead the combined defense posture, the South “should be capable of effectively countering North Korean ballistic nuclear missiles,” and the security environment of the Korean Peninsula “should be conducive to an OPCON transfer.”

Even though none of these conditions have been met, Moon had been insisting, until very recently, that OPCON transfer should be completed before the end of his presidential term. But the summit joint statement reiterates that OPCON transfer will depend on capabilities, to be determined by the US, and would not simply follow Moon’s timeline. The incoming commander of USFK, General Paul LaCamera, stated this policy distinctly in his confirmation before the US Congress.

Second, since the 2018 Singapore Summit between President Donald Trump and the North Korean leader Kim Jong Un, ROK-US combined military exercises have been postponed or canceled, initially by Trump’s unilateral decision and then by the 9/19 military agreement between the two Koreas’ militaries. Without such regular in-person field exercises to train Korean conscript forces and for Combined Forces Command (CFC) to practice, the combined defense posture against North Korea has seriously deteriorated. The long-established Ulchi Freedom Guardian, Key Resolve and Foal Eagle exercises have been called off, and the more limited Dong Maeng military exercises have been conducted virtually.

Despite this inadequate testing and verification of the combined defense posture, domestic criticism has been muted during the pandemic. At his congressional hearing, General LaCamera made clear that he will reassess the situation, putting more emphasis on in-person field exercises in the second half of 2021. Unfortunately, the summit joint statement did not clarify exactly how the combined defense posture would be enhanced, despite North Korea’s continued development of new ballistic missiles.

Third, this summit entirely failed to address the crucial issue of how to deter the North Korean nuclear and missile threats. It was agreed to drop restrictions on ROK missile development, in place since 1979, but this will not change the security situation, since longer-range missiles would upset China, probably resulting in renewed economic coercion of South Korea. Politically, Moon is still insisting that diplomatic efforts offering goodwill and generous inducements can persuade North Korea to abandon its nuclear weapons; however, few South Koreans or Americans really believe this, and the history of the Kim regime offers very little ground for such optimism.

Moon seems intent on pursuing his plan for peace and prosperity on the Korean Peninsula, and now he can point to Biden’s agreement that future talks with North Korea will be based upon the 2018 Panmunjom Declaration between Moon and Kim and the Singapore Joint Statement signed by Kim and Trump. The ROK military will see this as an empty victory, however, and will also be worried that Moon has moved South Korea a step closer to the US position of explicit containment of China, without knowing how China will respond, for example, by allowing North Korea more freedom for military provocations.

Some Challenges for the ROK-US Alliance

First, the ROK and the US need to decide upon a new mechanism to shape the future of the CFC. The Korea-US Integrated Defense Dialogue (KIDD) meeting is the natural forum for such discussions, but has previously been focused entirely on North Korea. Its current membership seems ill-prepared for a broader role extending to Taiwan and the SCS. Thus, despite KIDD holding a meeting on May 12-13 in Washington, DC, just ahead of the summit, there appeared to be little to no discussion of the future of CFC during the Biden-Moon summit. Only three real, substantive commitments relevant to the ROK-US alliance came out of the summit: Biden’s promise to provide COVID-19 vaccines for all of the 550,000 ROK Armed Forces (later raised to one million); the lifting of missile restrictions in place since 1979, so that the ROK military need no longer defer to the US in how it operates medium- and long-range missiles; and enhanced space-based technological cooperation between the ROK and US militaries. However, further discussion is needed to resolve fundamental differences between the ROK and US positions on the future of the alliance. For example, exactly how much strategic flexibility will USFK enjoy? Would a flare-up in the Senkaku/Diaoyu Islands justify the involvement of USFK? Ideally, a new crisis management system needs to be established, not only to respond to North Korean threats, but also for other regional security issues and specifically to ensure that the future CFC structure operates smoothly. Otherwise, OPCON transfer will certainly not be possible in the near to mid-term.

Second, the alliance needs to prepare a coherent plan for dealing with North Korea in the likely event that Moon’s final chance to achieve a peace settlement fails. Denuclearization is the declared goal, but as of yet, the details of North Korea’s nuclear weapons and missiles are still largely unknown, as not even the US can observe underground facilities and tunnels beneath airfields. Ultimately, the security of South Korea will depend on enhancing the effectiveness of the ROK-US combined defense posture, and with OPCON transfer still a moving target and the CFC expanding its remit as per the summit, the ROK and US militaries must start reworking their detailed operational plans.

Third, now that the ROK-US alliance is expanding its role to encompass regional security issues, such as the SCS and Taiwan’s security, new principles will be required for how to broaden coordination, particularly how to integrate USFK and US Forces Japan under the authority of the United Nations Command. This is within the remit of the US Global Force Posture Review. Both the summit press conference and the joint statement committed the ROK-US alliance to getting involved in sensitive regional issues by standing together to safeguard free and open navigation and promote a rules-based regional order and international law, but working out the details of this challenging vision will require a lot of work.


For the present, the ROK-US alliance remains intact, but there is considerable uncertainty about its future. “There is an expanded vision for the Indo-Pacific Strategy, in which South Korea plays a bigger regional and global role, both in security terms and more generally.” But it is unclear whether, beyond rhetoric, any real-world changes will result. The summit also provided very little information on what the US and South Korea are actually going to do about North Korea’s growing nuclear and missile threats. Indeed, there are significant differences between Moon and Biden on how to deal with North Korea, with Moon still hoping to make short-term progress on the inter-Korean peace initiative and the US still putting the issue of denuclearization first. Despite the positive tone of the summit and Moon’s endorsement of the Biden administration’s new negotiating strategy, there were no indications of how to get the North Koreans back to the table.

While the summit joint statement will be presented as a win for both presidents, Moon has been obliged to tilt the South toward the United States’ policy on China, and to that extent, the Biden administration emerged from the summit in a stronger position than the South Korean government.

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